Luisv
04-13-2020, 07:12 PM
It's a common issue on Gen 2 Vipers. The Relays that control the fan burn the sockets on the power distribution center (PDC). There is a solution out there that many of us point to which was done and written up by MOTOiQ for a project Viper Gen 2. It is great and goes into a good amount of detail. It is the basis for what I did. All I am doing here is bringing it to the forum with some details for those that may find it helpful and dont search or find the MOTOiQ info. I have been asked about this on facebook as well so I simply wanted to do this to have something to point to. I have seen other solutions, some more exotic/fancy than others, but this one is clean, simple to do and relatively cheap.
Running hot on a Gen 2 is common. Before I did this fix, I tried other things. For example higher rated relays. I also tried Roe Racing's Fan Control. Honestly, it does kill your battery if you don't run a tender. However, to be fair it did work well for me for a good while. The main thing is that it cools the car down by ruinning the fan after you shut off the ignition. What it help most with is heat soaking into the cabin and running air through the evaporator core getting it cool quickly for the next time you jump into a 150 degree interior in Florida and turn on the A/C to avoid heat stroke. However, it too had an issue eventually (it took years). This is what happened one day with the Roe Kit that ultimately made me move to a re-wire of the stock fan system. I don't know, but I'm leaning towards overheating as being the culprit there.
https://i.imgur.com/JyCoWNd.jpg
The basic problem is that the relays that run the fans overheat at the load leg (Pin 87 on the relay) when the fan is running. When they overheat two things can happen. First the relay is damaged. Second the socket in the PDC melts. Sometimes so badly that the wiring itself is damaged to the point that the PDC has to be replaced. Below is the wiring for the fan that controls both the on/off and high/low speed options. They use two Bosch style 5 pin relays to control this.
https://i.imgur.com/RMzsWYY.jpg
The setup is pretty simple and works off of Bosch style 5 pin relays. The way it works is that pin 85 (ground) & 86 (signal) are the “switch”. Pin 30 is the power or input. Pins 87 & 87A are the output pins. Pin 87A is connected to Pin 30 when there is no voltage applied to Pin 86. This is the default state. If you want nothing to get power, then you simply leave no load connected to pin 87A. When voltage or a signal goes to pin 86 then the relay switched over to pin 87 and then power from pin 30 is applied to that load.
In the case of the Viper, the on/off relay gets a signal from the ECU to Pin 86 (at 207 degrees) which applies power to Pin 87. This in turn applies power to Pin 30 of the speed control relay. This essentially turns on the fan. The speed control relay uses both pins 87A and 87. In the default state (when engine temp is between 207 and 215) the relay is giving power to Pin 87A and the fan runs at low speed. When the temperature hits 216 degrees then the ECU sends the signal to Pin 86 on the speed relay. This then sends power to Pin 87 instead of 87A and that turns the fan to high speed.
This setup works but what ends up happening is that the current flowing through the PDC and relays is high. This causes the system to melt the plastic at the terminals. To eliminate that what we are going to do is use the stock setup to provide signal to the new circuit. In short, the stock relays and PDC are used but the current will be very low. You are not powering the fan with the stock relays.
The new circuit we will be mounting to the fan shroud is below:
https://i.imgur.com/EAO5QUr.jpg
The Gen 2 Factory Fan Wiring now supplies the “signals” for the New 50A Relay Wiring. The factory connector at the chassis/frame that used to power the fan directly now will just provide the signal and the current will be minimal through that. On the new circuit there is dedicated 12V and ground 10 AWG marine grade wire supplying the power to run the fan. This will be much more than enough to handle 50A. The dedicated 12V feeds Pin 30 on both relays. From there each relay has 10 AWG marine grade wire coming from each relay Pin 87 to the fan. Bottom line the fan has 10 AWG wire providing the power for the fan. With the new circuit, one relay runs the low speed, the other runs the high speed.
Now that we have the details of how this is going to work some details on the parts. Since we are running the system on dedicated power from 12V, you need some way to fuse/protect the circuit. The way they MOTOiQ did it was with a breaker. You could do the same with a fuse. Essentially the breaker does the same function and you can reset it if it trips. The breaker I used was:
PN/ CB3-SM-60 from Terminal Supply Company (online)
TYPE III SURFACE MOUNT 60 AMP MANUAL RESET
https://i.imgur.com/Cu41nSL.jpg
For the ciruit like I showed in my diagram, you will need two more items. The relays themselves and the sockets with pigtails. Those are:
PN/ TYR-032-1250
TYCO/BOSCH RELAY W/RESISTOR 50A 12V
PN/ PT-BOS-12BK
BOSCH RELAY PIGTAILS THREE 12GA & TWO 16GA WIRE LEADS
[img]https://i.imgur.com/Us9lcBB.jpg
https://i.imgur.com/RZYz5kq.jpg
The relay socket is interlocking meaning the two sockets can be interlocked so that the relays sit immediately next to each other. This eases the mounting. The sockets also have 12 AWG leads for the power and load wires (Pins 30, 87A and 87) and two 16 AWG wires for the signal leads (Pins 85 & 86).
In addition to that, the MOTOiQ setup puts in two arc supressors. These basically protect the relays from damage due to the on/off sequences. It removes sparks in the relay. I did not include that in my circuit drawing but I did install them in the car. Realistically, the supressors are good to have, but are not "required" to make it work. In the interest of simplicity and clarity, I left them out of the circuit drawing. If you would like to add them you would need two NOsparc units. Each one goes (wired in parallel) between Pin 30 and Pin 87 on each relay socket/pigtail. In other words, they go wired across the wires in my diagram. They do not get wired in line on one wire/pigtail. You can see how on the MOTOiQ site. The product info and details are here:
https://www.arcsuppressiontechnologies.com/products/dc-nosparc-products-2/
and the product part is below:
https://i.imgur.com/mc0pmkY.jpg
I will not go into huge detail from here as it would be simply reproducing a writeup and info from MOTOiQ site. I'll just show you the step by step and how I finished up the wiring and how I mounted it to the fan shroud.
Depending on the car, you may have a fan motor with a pigtail coming from it (like mine) or your connector may be hard wired to the fan motor itself. Below is the pigtail. It has a notched oval connector on the motor side and an oval connector that goes to the male end coming from the chassis. If you have the pig tail, you will cut that in the center because you will reuse both sides.
https://i.imgur.com/LxsIkty.jpg
https://i.imgur.com/3EBUJTO.jpg
Once the pigtail is out, this is what you have to work with. The clean fan shorud and fan.
https://i.imgur.com/FK6uunP.jpg
On the side facing the radiator, I applied reflective heat shielding. This keeps the heat off of the areas where we will be mounting the components. In addition to that, I applied small pieces of the same heat shielding to the connectors themselves. (I did not take of photo of the device backs, but it's there). The heat shield I used is picked up from any auto parts store and is made by DEI.
https://i.imgur.com/ZKqC2Fy.jpg
The heat shielding applied to the shroud, again, this will face the radiator. I applied it on both the passenger and drive side of the fan.
https://i.imgur.com/dKQRPSq.jpg
https://i.imgur.com/ATINHDa.jpg
The components are mounted as follows. The Breaker is mounted on the drivers side of the fan. This is where the dedicated power and factory connector (which will simply be a signal system now) come from.
https://i.imgur.com/moT9MVp.jpg
In the photo above, you will see the Ornage (dedicated 12V supply wire) attached to the top left bolt/post. The bottom right post in the out wire to the relays that ultimately will go to pin 30 on each relay. The bottom left and top right bolts in the image are the screws that mount the breaker to the fan shroud. I drilled the two holes and simply mounted the breaker. The black wires on the bottom left post are the common/ground wires. I used the mounting post bolt as my connection point for the grounds.
The passenger side gets the relays and NOsparcs (optional, but I installed them). Those are also bolted in place and have reflective heat shielding as well. The NOsparcs are also mounted with some delrin bushings to keep them off the plastic shroud. This is just to leave a small gap for cooling separation off the fan shroud.
https://i.imgur.com/cwuN2w0.jpg
Once the hardware is mounted, I wired it all up. In this shot, you'll see I used simple crimp/butt copnnectors to make most of the connections. I also left all the wires hanging long and loose. This was simply to be able to test everything before I clean it all up. The wires are all connected and run as they are shown in the circuit diagram.
https://i.imgur.com/iBjMffr.jpg
I then mounted the fan (with just one nut holding it) in the car and then connected the dedicated 12V to the positive post on the PDC (top of the photo) and the dedicated ground to the chassis ground under the PDC on the sill directly inward from the side sill cover. (bottom of image)
https://i.imgur.com/eBRiDQ5.jpg
I then tested the circuit to see if it ran as planned. To test this, you do not have to run the engine. All you need to do is take out both of the FACTORY relays in the PDC and then use a jumper cable to jump across from Pin 30 (check the circuit diagram or look under the relay you removed to see what Pin 30 is) to Pin 87. You will need two jumper "wires" to test the on/off of the fan (low Speed) and the (high/low) that will switch to high speed mode. The two fan relays are in the squarte box in front of the 12V power post. The two outside (driver's side) relays are the fan relays. Of those two the one closer to the front of the car is the on/off (low speed) relay and the rear is the speed relay.
In order to test the system. The engine does not need to and should not be running.
1. Remove both factory relays
2. On the relay closest to the FRONT of the car, place a jumper wire across Pin 30 (of the three middles pins, the outside that runs parallel to the radiator) and Pin 87 (inner pin of middle row that runs perpendicular to Pin 30)
3. On the relay closest to the REAR of the car, place a jumper wire across Pin 30 (of the three middles pins, the outside that runs parallel to the radiator) and Pin 87A (middle/center pin of middle row that runs perpendicular to Pin 30)
Once you do that, you should hear the fan spin up in low speed.
4. On the relay closest to the REAR of the car, place a jumper wire across Pin 30 (of the three middles pins, the outside that runs parallel to the radiator) and Pin 87 (inner pin of middle row that runs perpendicular to Pin 30)
Once you do that, you will hear the fan spin up in high speed.
Do not leave the jumpers in place. Simply do this to test.
If everything is wired correctly, then you will hear the fan change speeds depending on what pins are jumped on the rear relay. Remove all the jumpers and take the assembly out again. Now we make everything pretty and tighten it all up.
I made all the connections with crimps and then soldered the crimps. Everything is then covered in heat shrink.
https://i.imgur.com/cmAT6Ld.jpg
https://i.imgur.com/t9JwVYt.jpg
Take your time here. Measure well, plan each wire run and figure out where to place the wire runs. In my case, I ran the wires and tie wrapped to the "fins" on the shroud for the "signal wires" and the 10 AWG power and ground wires, along with the wires going to the fan motor connector, ran under the fan shroud. Everything, again, in heat shrink to clean everything up as much as possible. The one thing I'd like to mention is that MOTOiQ added a new connector/plug/ to be able to connect and disconnect the dedicated power and ground. I decided to run those straight to the breaker block with a round terminal on it. For me, it's one less connector to fail. It means I have to remove the wires by removing the nuts on the breaker if I have to take the fan out. Oh well.... Not planning on doing that every weekend so I should be good.
The final result with everything tied down and covered.
https://i.imgur.com/RjG8taY.jpg
Hope this helps and hit me up for any questions.
Running hot on a Gen 2 is common. Before I did this fix, I tried other things. For example higher rated relays. I also tried Roe Racing's Fan Control. Honestly, it does kill your battery if you don't run a tender. However, to be fair it did work well for me for a good while. The main thing is that it cools the car down by ruinning the fan after you shut off the ignition. What it help most with is heat soaking into the cabin and running air through the evaporator core getting it cool quickly for the next time you jump into a 150 degree interior in Florida and turn on the A/C to avoid heat stroke. However, it too had an issue eventually (it took years). This is what happened one day with the Roe Kit that ultimately made me move to a re-wire of the stock fan system. I don't know, but I'm leaning towards overheating as being the culprit there.
https://i.imgur.com/JyCoWNd.jpg
The basic problem is that the relays that run the fans overheat at the load leg (Pin 87 on the relay) when the fan is running. When they overheat two things can happen. First the relay is damaged. Second the socket in the PDC melts. Sometimes so badly that the wiring itself is damaged to the point that the PDC has to be replaced. Below is the wiring for the fan that controls both the on/off and high/low speed options. They use two Bosch style 5 pin relays to control this.
https://i.imgur.com/RMzsWYY.jpg
The setup is pretty simple and works off of Bosch style 5 pin relays. The way it works is that pin 85 (ground) & 86 (signal) are the “switch”. Pin 30 is the power or input. Pins 87 & 87A are the output pins. Pin 87A is connected to Pin 30 when there is no voltage applied to Pin 86. This is the default state. If you want nothing to get power, then you simply leave no load connected to pin 87A. When voltage or a signal goes to pin 86 then the relay switched over to pin 87 and then power from pin 30 is applied to that load.
In the case of the Viper, the on/off relay gets a signal from the ECU to Pin 86 (at 207 degrees) which applies power to Pin 87. This in turn applies power to Pin 30 of the speed control relay. This essentially turns on the fan. The speed control relay uses both pins 87A and 87. In the default state (when engine temp is between 207 and 215) the relay is giving power to Pin 87A and the fan runs at low speed. When the temperature hits 216 degrees then the ECU sends the signal to Pin 86 on the speed relay. This then sends power to Pin 87 instead of 87A and that turns the fan to high speed.
This setup works but what ends up happening is that the current flowing through the PDC and relays is high. This causes the system to melt the plastic at the terminals. To eliminate that what we are going to do is use the stock setup to provide signal to the new circuit. In short, the stock relays and PDC are used but the current will be very low. You are not powering the fan with the stock relays.
The new circuit we will be mounting to the fan shroud is below:
https://i.imgur.com/EAO5QUr.jpg
The Gen 2 Factory Fan Wiring now supplies the “signals” for the New 50A Relay Wiring. The factory connector at the chassis/frame that used to power the fan directly now will just provide the signal and the current will be minimal through that. On the new circuit there is dedicated 12V and ground 10 AWG marine grade wire supplying the power to run the fan. This will be much more than enough to handle 50A. The dedicated 12V feeds Pin 30 on both relays. From there each relay has 10 AWG marine grade wire coming from each relay Pin 87 to the fan. Bottom line the fan has 10 AWG wire providing the power for the fan. With the new circuit, one relay runs the low speed, the other runs the high speed.
Now that we have the details of how this is going to work some details on the parts. Since we are running the system on dedicated power from 12V, you need some way to fuse/protect the circuit. The way they MOTOiQ did it was with a breaker. You could do the same with a fuse. Essentially the breaker does the same function and you can reset it if it trips. The breaker I used was:
PN/ CB3-SM-60 from Terminal Supply Company (online)
TYPE III SURFACE MOUNT 60 AMP MANUAL RESET
https://i.imgur.com/Cu41nSL.jpg
For the ciruit like I showed in my diagram, you will need two more items. The relays themselves and the sockets with pigtails. Those are:
PN/ TYR-032-1250
TYCO/BOSCH RELAY W/RESISTOR 50A 12V
PN/ PT-BOS-12BK
BOSCH RELAY PIGTAILS THREE 12GA & TWO 16GA WIRE LEADS
[img]https://i.imgur.com/Us9lcBB.jpg
https://i.imgur.com/RZYz5kq.jpg
The relay socket is interlocking meaning the two sockets can be interlocked so that the relays sit immediately next to each other. This eases the mounting. The sockets also have 12 AWG leads for the power and load wires (Pins 30, 87A and 87) and two 16 AWG wires for the signal leads (Pins 85 & 86).
In addition to that, the MOTOiQ setup puts in two arc supressors. These basically protect the relays from damage due to the on/off sequences. It removes sparks in the relay. I did not include that in my circuit drawing but I did install them in the car. Realistically, the supressors are good to have, but are not "required" to make it work. In the interest of simplicity and clarity, I left them out of the circuit drawing. If you would like to add them you would need two NOsparc units. Each one goes (wired in parallel) between Pin 30 and Pin 87 on each relay socket/pigtail. In other words, they go wired across the wires in my diagram. They do not get wired in line on one wire/pigtail. You can see how on the MOTOiQ site. The product info and details are here:
https://www.arcsuppressiontechnologies.com/products/dc-nosparc-products-2/
and the product part is below:
https://i.imgur.com/mc0pmkY.jpg
I will not go into huge detail from here as it would be simply reproducing a writeup and info from MOTOiQ site. I'll just show you the step by step and how I finished up the wiring and how I mounted it to the fan shroud.
Depending on the car, you may have a fan motor with a pigtail coming from it (like mine) or your connector may be hard wired to the fan motor itself. Below is the pigtail. It has a notched oval connector on the motor side and an oval connector that goes to the male end coming from the chassis. If you have the pig tail, you will cut that in the center because you will reuse both sides.
https://i.imgur.com/LxsIkty.jpg
https://i.imgur.com/3EBUJTO.jpg
Once the pigtail is out, this is what you have to work with. The clean fan shorud and fan.
https://i.imgur.com/FK6uunP.jpg
On the side facing the radiator, I applied reflective heat shielding. This keeps the heat off of the areas where we will be mounting the components. In addition to that, I applied small pieces of the same heat shielding to the connectors themselves. (I did not take of photo of the device backs, but it's there). The heat shield I used is picked up from any auto parts store and is made by DEI.
https://i.imgur.com/ZKqC2Fy.jpg
The heat shielding applied to the shroud, again, this will face the radiator. I applied it on both the passenger and drive side of the fan.
https://i.imgur.com/dKQRPSq.jpg
https://i.imgur.com/ATINHDa.jpg
The components are mounted as follows. The Breaker is mounted on the drivers side of the fan. This is where the dedicated power and factory connector (which will simply be a signal system now) come from.
https://i.imgur.com/moT9MVp.jpg
In the photo above, you will see the Ornage (dedicated 12V supply wire) attached to the top left bolt/post. The bottom right post in the out wire to the relays that ultimately will go to pin 30 on each relay. The bottom left and top right bolts in the image are the screws that mount the breaker to the fan shroud. I drilled the two holes and simply mounted the breaker. The black wires on the bottom left post are the common/ground wires. I used the mounting post bolt as my connection point for the grounds.
The passenger side gets the relays and NOsparcs (optional, but I installed them). Those are also bolted in place and have reflective heat shielding as well. The NOsparcs are also mounted with some delrin bushings to keep them off the plastic shroud. This is just to leave a small gap for cooling separation off the fan shroud.
https://i.imgur.com/cwuN2w0.jpg
Once the hardware is mounted, I wired it all up. In this shot, you'll see I used simple crimp/butt copnnectors to make most of the connections. I also left all the wires hanging long and loose. This was simply to be able to test everything before I clean it all up. The wires are all connected and run as they are shown in the circuit diagram.
https://i.imgur.com/iBjMffr.jpg
I then mounted the fan (with just one nut holding it) in the car and then connected the dedicated 12V to the positive post on the PDC (top of the photo) and the dedicated ground to the chassis ground under the PDC on the sill directly inward from the side sill cover. (bottom of image)
https://i.imgur.com/eBRiDQ5.jpg
I then tested the circuit to see if it ran as planned. To test this, you do not have to run the engine. All you need to do is take out both of the FACTORY relays in the PDC and then use a jumper cable to jump across from Pin 30 (check the circuit diagram or look under the relay you removed to see what Pin 30 is) to Pin 87. You will need two jumper "wires" to test the on/off of the fan (low Speed) and the (high/low) that will switch to high speed mode. The two fan relays are in the squarte box in front of the 12V power post. The two outside (driver's side) relays are the fan relays. Of those two the one closer to the front of the car is the on/off (low speed) relay and the rear is the speed relay.
In order to test the system. The engine does not need to and should not be running.
1. Remove both factory relays
2. On the relay closest to the FRONT of the car, place a jumper wire across Pin 30 (of the three middles pins, the outside that runs parallel to the radiator) and Pin 87 (inner pin of middle row that runs perpendicular to Pin 30)
3. On the relay closest to the REAR of the car, place a jumper wire across Pin 30 (of the three middles pins, the outside that runs parallel to the radiator) and Pin 87A (middle/center pin of middle row that runs perpendicular to Pin 30)
Once you do that, you should hear the fan spin up in low speed.
4. On the relay closest to the REAR of the car, place a jumper wire across Pin 30 (of the three middles pins, the outside that runs parallel to the radiator) and Pin 87 (inner pin of middle row that runs perpendicular to Pin 30)
Once you do that, you will hear the fan spin up in high speed.
Do not leave the jumpers in place. Simply do this to test.
If everything is wired correctly, then you will hear the fan change speeds depending on what pins are jumped on the rear relay. Remove all the jumpers and take the assembly out again. Now we make everything pretty and tighten it all up.
I made all the connections with crimps and then soldered the crimps. Everything is then covered in heat shrink.
https://i.imgur.com/cmAT6Ld.jpg
https://i.imgur.com/t9JwVYt.jpg
Take your time here. Measure well, plan each wire run and figure out where to place the wire runs. In my case, I ran the wires and tie wrapped to the "fins" on the shroud for the "signal wires" and the 10 AWG power and ground wires, along with the wires going to the fan motor connector, ran under the fan shroud. Everything, again, in heat shrink to clean everything up as much as possible. The one thing I'd like to mention is that MOTOiQ added a new connector/plug/ to be able to connect and disconnect the dedicated power and ground. I decided to run those straight to the breaker block with a round terminal on it. For me, it's one less connector to fail. It means I have to remove the wires by removing the nuts on the breaker if I have to take the fan out. Oh well.... Not planning on doing that every weekend so I should be good.
The final result with everything tied down and covered.
https://i.imgur.com/RjG8taY.jpg
Hope this helps and hit me up for any questions.