Rad fan won't turn on. Help please

[BrianACR]

I have a '01 GTS ACR. As I was out and about last night, I noticed my engine starting to get rather hot as i was sitting at stoplights. My rad fan wasn't kicking on. I checked the fuses and they were fine, but what else could be causing the fan not to come on as the engine temp goes up??? What things do I need to look at and make sure they are working?

[Steve-Indy]

Fan relays...there are two in the small square box just forward of the main fuse/relay box.

[dave6666]

More specifically, fan relay base plug melting. Also, the connector at the fan itself will melt, and the thermostat if bad can cause this problem you are having.

BTW, there are many ways to alter the fan current control. Anything short of removing the load from the PDC and ridding it of any electromechanical relays is just a bandaid.

[Fatboy 18]

I have a '01 GTS ACR. As I was out and about last night, I noticed my engine starting to get rather hot as i was sitting at stoplights. My rad fan wasn't kicking on. I checked the fuses and they were fine, but what else could be causing the fan not to come on as the engine temp goes up??? What things do I need to look at and make sure they are working?

Hi Brian,
Do you have A/C? If you do, try switching that on as it kicks in the high speed fan and you should notice the temp start to fall back.
Also found this article
http://www.motoiq.com/MagazineArticl...g-Upgrade.aspx

Also read this thread,
Dave posted up some really helpful pics of his set up
http://driveviper.com/forums/threads...-problem-again!

Thank's Dave

[dave6666]

Hi Brian,
Do you have A/C? If you do, try switching that on as it kicks in the high speed fan and you should notice the temp start to fall back.
Also found this article
http://www.motoiq.com/MagazineArticl...g-Upgrade.aspx

Sadly, the relocation of the factory type electromechanical relays does not remove the problems inherent with electromechanical relays lol.

[Darth Menace]

Brian, if those relays readily available locally you can test mine to see if that is the issue

[BrianACR]

Thanks for all the tips guys. Much appreciated. Just got back from a weekend away so hopefully i'll have a chance too look a bit more into the issue now.

[BrianACR]

So I went in an checked all the fuses and realys. Everything was ok. Checked any connections that I could find. Again, everything was good. No burn marks or melted spots. I fired her up and let her get warm. Sure enough, the fan works now. Not sure if something had been knocked loose on a recent trip I made. Hit a couple big bad bumps that came out of nowhere. Maybe a connection or relay got jarred loose. Who knows?? Have to wait and see if it does it again or not.
Thanks again for all the tips.

[ICPREY]

May want to check the connector at the fan on the bottom of it for corrosion.

[dave6666]

May want to check the connector at the fan on the bottom of it for corrosion.

Been covered brah

[fuggles]

Also relays have a habit of sticking and a tap will sometimes cause them to work again.

[Luisv]

When you run the car check the temp gauge when the fan turns on for the first time. Then turn on A/C and see if the fans go to high speed. If it doe not it might be the fan motor itself. If it does, turn the A/C off as soon as possible and let the engine get hotter. The high speed should come on when the temp hits 215 (if memory serves, I'll have to check the service manual to be sure). If it does not, there may be a temp sensor problem. By checking the A/C first, you will see that the fan does or does not go to high speed. Once there, waiting for the car to get hotter will show if there might be an issue with the sensor.

As for the melting connections for the Relays, I would say that it's more likely to occur on older second gens or gen I cars. The later Gen 2's like yours has a larger/more powerful fan and better gauge wiring at the relay block. What heats up is the wire, not the block. Still, that does not mean the block and relays can't melt, but it's more likely to happen on earlier cars.

I'd get a new set of relays (they're cheap) and have them all replaced. The four in there are all the same. You'll have that out of the way and known good.

[dave6666]

When you run the car check the temp gauge when the fan turns on for the first time. Then turn on A/C and see if the fans go to high speed. If it doe not it might be the fan motor itself. If it does, turn the A/C off as soon as possible and let the engine get hotter. The high speed should come on when the temp hits 215 (if memory serves, I'll have to check the service manual to be sure). If it does not, there may be a temp sensor problem. By checking the A/C first, you will see that the fan does or does not go to high speed. Once there, waiting for the car to get hotter will show if there might be an issue with the sensor.

As for the melting connections for the Relays, I would say that it's more likely to occur on older second gens or gen I cars. The later Gen 2's like yours has a larger/more powerful fan and better gauge wiring at the relay block. What heats up is the wire, not the block. Still, that does not mean the block and relays can't melt, but it's more likely to happen on earlier cars.

I'd get a new set of relays (they're cheap) and have them all replaced. The four in there are all the same. You'll have that out of the way and known good.

Your reply points out the misunderstanding of the heat sources that can damage the relays and PDC itself.

* The fact that the relays are enclosed in that small non-ventilated box (the PDC...) that's right in the airflow path of the hot engine compartment is a big problem. Replacing the relays or upping their amp rating does nothing to address that, although "new" relays are better than "old" relays.

* Heat is inherent to an electromechanical relay. New ones heat up, and higher amp rating relays will heat up too.

* The connections to the relays themselves are spring loaded contacts. That 1/4" blade. Down inside the PDC below that red plastic are the spring loaded terminals. People will solder the wires to the spring terminal wire connection crimp. Which does nothing to address it's a spring terminal connection to the relay. And neither does installing new relays or higher amp rated relays. You still have spring connections to the relays. A spring connection is a high resistance connection as compared to a bolted electrical connection. That's the better option.

The only way to permanently address all of these things is to remove the fan load from the PDC. And preferably replace the electromechanical relays with something more robust for that demanding of a current load. The technology to do that is available. But sadly you have to build your own.

[Steve-Indy]

Dave, you have addressed this issue in the past...and, described how you actually substituted your solution for the fan relays. Unfortunately, I am having trouble finding that discussion on both this and the VCA Forum.

Would you consider either re-describing your solution or posting a link to same. Either way thanks...and, I will keep searching.

[Fatboy 18]

Dave, you have addressed this issue in the past...and, described how you actually substituted your solution for the fan relays. Unfortunately, I am having trouble finding that discussion on both this and the VCA Forum.

Would you consider either re-describing your solution or posting a link to same. Either way thanks...and, I will keep searching.

Hi Steve, there are some pictures of Dave's work here and Wiring diagrams.
http://driveviper.com/forums/threads...-problem-again

[Steve-Indy]

Many thanks, Mark !!

[Steve-Indy]

Nice...thanks...to you and Dave !!

[SlowPoke McGee]

Hey Brian. Did you ever find a cure to this? I notice my car also does this from time to time.

[Coloviper]

I followed Dave's blue print, I just mounted mine in a different location. Here's a pic



Attachment 18824

Are you running a remote fuel pressure relay right on top your fuse box? I would say "noooooooooo" when I first saw that.

[BrianACR]

Hey Brian. Did you ever find a cure to this? I notice my car also does this from time to time.

It seemed to work just fine once I got in and checked all the fuses and relays. I'm thinking something might have been jarred loose courtesy of all the wonderful smooth roads on the henday construction. After I pulled all them out and out 'em back in, it worked just fine.