Radiator Fan Not Coming On...'96 RT

[Matt M, Pa]

Well, I guess the title sums it up. Went out for a short ride tonight, and on my way back had to stop for some traffic. The temperature gauge had gone up to the mark at about 2 o'clock. It kept climbing slowly, and once I was able to start moving it had gotten close to the 250 mark...but did not quite reach it. I was close to home so I got some speed going and turned the heat on. The temp came down quickly and by the time I got home it was normal.

I let the car cool down a bit and went back to the garage to check it out. With the engine idling, the fan does not turn at all. When the A/C is turned on, the fan does not turn. (When checking this, the gauge read somewhere around 11 o'clock)

I seem to remember the car doing something similar a few summers ago but when I checked it.....the fan ran and it's been fine since. In fact, when stopped at longer lights, etc.. the gauge would gradually climb to the mark at about 2 o'clock and then the fan would come and it would cool down.

I do know that the first relay visible relay on the HVAC box is the "on" relay, but I wasn't able to get it unplugged as it's stiff and the car is still warm.

So guys...where to start? If I can get that darned relay unplugged I'll jump it and see if the fan runs.

Finally, looking at old receipts from the previous owner, it appears this happened in 2005...an DC Performance diagnosed it to be the relays...

I'm thankful for any thoughts...

[Fatboy 18]

Lots of threads on this....
http://driveviper.com/forums/threads...on-Help-please


http://driveviper.com/forums/threads...-problem-again

This is a get out of jail get you home relay bypass 30amp fused link, remove Low speed Fan relay and plug in fused link, the fan will come on straight away weather the ignition is on or off and WILL STAY ON! Those wires will get hot, (Very Hot). But it's a good way to test that the fan is working.

Fuse link temporary fix, with 30amp fuse

[dave6666]

Yes as FB already pointed out review a few key electrical areas.

* fan fuses
* fan relays; pull them to inspect for melting under them or possibly swap them out with new ones
* pull the fan wiring harness connector apart and inspect both sides for melting up in the pin area

There are plenty of fixes for each of these issues if you discover one. Some of those fixes are just bandaids and don't really address root causes. Choose your path forward wisely.

[Matt M, Pa]

Thanks guys...this is a Gen 1 engine compartment...so a bit different than above.

Please correct me if I'm wrong, but I believe these cars have a fusible link, and no fuse. The relays are also installed in a different place/perhaps configuration. That being said, I'm sure I can make up a bypass to test.

If I see it correctly, the gen 1 use a standard relays...I have several and can test with new ones. WIll also examine the wiring.

Thanks again...will report back. I have also considered the kit Sean Roe sells for these cars to control the fan...

[dave6666]

Thanks guys...this is a Gen 1 engine compartment...so a bit different than above.

Please correct me if I'm wrong, but I believe these cars have a fusible link, and no fuse. The relays are also installed in a different place/perhaps configuration. That being said, I'm sure I can make up a bypass to test.

If I see it correctly, the gen 1 use a standard relays...I have several and can test with new ones. WIll also examine the wiring.

Thanks again...will report back. I have also considered the kit Sean Roe sells for these cars to control the fan...

Do not skip inspecting the electrical items like the fan wiring harness connector and the base of the PDC where the relays plug in. Or wherever they plug in Gen 1. Those are common problems that are hidden from sight and if you try to force the issue of fan operation w/o first correcting those they can propagate into other bigger issues.

[dodgestang]

I had this issue 2-3 weeks ago on my 96 GTS....ultimate solution employed by a shop I had doing work was replacing the relay and a new fan.

[dave6666]

I had this issue 2-3 weeks ago on my 96 GTS....ultimate solution employed by a shop I had doing work was replacing the relay and a new fan.

Interesting that both of those would expire at the same time. Did you, or them by any chance, look at the fan connector and relay base to see if they were damaged? On the old parts?

[SnakeWatching]

The first thing I did on my 97 GTS was to pull all relays and coat the contacts with conductive grease.

While I understand the issues with melting connections (read most of all the posts on both sites), I do wonder if it all starts with corrosion - which in turn makes the connection a resistor - which in turn heats up as corrosion gets worse and current is applied. (I could be wrong - just my opinion above).

[dodgestang]

Per tech relay was bad and it fried the fan motor

[Matt M, Pa]

Thanks guys! I'm crazy right now with work but will hopefully get a chance over the weekend to check it out.

In the little bit of time I played with getting the relay unplugged, I found a small "key" that retains the relay to the bracket. Now...it's not easy to unplug or lift that relay off the bracket due to it's location. Once thing I did notice was that the hardness plugged into the relay actually seems to have some play compared to the others.

For now...I just need to figure how the heck to get the leverage to disconnect the darned thing. It's under the HVAC fan motor and behind the A/C receiver-dryer....

[dave6666]

Thanks guys! I'm crazy right now with work but will hopefully get a chance over the weekend to check it out.

In the little bit of time I played with getting the relay unplugged, I found a small "key" that retains the relay to the bracket. Now...it's not easy to unplug or lift that relay off the bracket due to it's location. Once thing I did notice was that the hardness plugged into the relay actually seems to have some play compared to the others.

For now...I just need to figure how the heck to get the leverage to disconnect the darned thing. It's under the HVAC fan motor and behind the A/C receiver-dryer....

That play could be from heat softening the plastic stuff that holds the terminals on the other side. Those relay terminals, the ones you usually can't see because they are on the back side of an enclosure, are nothing more than common 1/4" wide female blade crimps with no barrel insulation and a small retaining tab added. Which is the inherent flawed design that using those in high current applications has. Getting rid of that type of relay altogether is the ultimate solution, albeit the most involved.

[dave6666]

Per tech relay was bad and it fried the fan motor

That is quite odd. Relays like that are simply switches. They are on, or off. And when bad, they don't turn on. In your case, as well as a general possibility using relays to switch motor current, if the contacts had not quite failed yet and were supplying partial voltage to the motor, that could have damaged the motor I guess. But it sounds to me like it was a great opportunity to sell a fan motor to someone... Glad you got your car fixed tho. Hopefully the problem will stay away for a while.

[Matt M, Pa]

An update. Remove the on off fan relay, and plugged in a standard relay that I had in my toolbox. Fan works fine.

So, went to Napa, and they can't find a listing for it. Does anybody have a part number for the NAPA replacement relay? The only thing the could find was a standard relay with a tab and a hole to connect to the vehicle.

Anyhow...came back home and was hoping to see a way to put the guts of a replacement relay in the original case. While I think that can be done...it gave me a chance to look at the original relay. It has no continuity through 87 & 30...so it seems to be good. The terminals were a bit tarnished, so I cleaned them up with an emery board and tested it in the car. Fan works correctly coming on just before the mark on the gauge @ 2 o'clock...shutting off around the right mark in the middle. Also turns on with the A/C.

The wiring, etc all looked good with no melting, etc. Same for the fan plug, etc. I'm surprised that's all it was...,but I'm not complaining.

Thanks again guys...and if anyone can give me a part # to get a backup relay from NAPA...I'd sure appreciate that.

[dave6666]

They are standard cube relays. The fact that an auto parts store cannot cross reference to one simply shows you how useless auto parts stores are.

[dave6666]

http://www.wiringproducts.com/automotive-relays

[dodgestang]

That is quite odd. Relays like that are simply switches. They are on, or off. And when bad, they don't turn on. In your case, as well as a general possibility using relays to switch motor current, if the contacts had not quite failed yet and were supplying partial voltage to the motor, that could have damaged the motor I guess. But it sounds to me like it was a great opportunity to sell a fan motor to someone... Glad you got your car fixed tho. Hopefully the problem will stay away for a while.

Considering they didn't sell me the fan, I had to go elsewhere for it and they didn't charge me for the relay....I wasn't too worried and/or seeing nefarious intention.

[Matt M, Pa]

Thanks for the link, dave6666. I have several of the standard relays, but all have the tab with a hole to hang them as opposed to the housing that slides onto the factory bracket.

But...seeing the ones in your link without the tab makes me wonder if Chrysler didn't just make that housing to hold one of those.

[Viper Red]

My take would be a bad fan motor which is drawing over current from the wiring and heating up the insulators on your wires and perhaps frying the relay in the process.
Circuit control or protection devices do not damage actual end devices, the other way is very very possible.