Engine cooling fans

[King Peetis]

I would suggest checking the fan switch you got. Chances are the salesperson might have confused them

I checked the old ones I replaced a while ago. The one at the rad. bottom is stamped "90M" whereas the other at the thermostat housing is stamped "108", which I bet those are Celsius temps (108C is above 212 F)
Anyway, it is possible to install the high temp switch where the low temp goes; I checked the connectors and both are the same.

Hope it helps.

Good looking out! I'll take a look. I stopped by pull a part and grabbed a handful of relays and fuses. I also picked up a new fuse box cover with a good diagram on top. I had no idea what was what in that box without the diagram. This coming weekend, Im gonna go through the motions and start trouble shooting all over again.

[ecogabriel]

Good looking out! I'll take a look. I stopped by pull a part and grabbed a handful of relays and fuses. I also picked up a new fuse box cover with a good diagram on top. I had no idea what was what in that box without the diagram. This coming weekend, Im gonna go through the motions and start trouble shooting all over again.

I now realized we live in the same area. I kept the old working switches so if you want to do some testing I may pass them on to you. I live about 3 mi. away from I-78 and I-285. PM me

[King Peetis]

I now realized we live in the same area. I kept the old working switches so if you want to do some testing I may pass them on to you. I live about 3 mi. away from I-78 and I-285. PM me

Thanks for the offer, but I think Im good on parts. We should hook up anyway just to shoot the bull and do a little trouble shooting-I'll PM you tonight.

[Dr_Snooz]

Let us know what you learn. It seems cooling fan problems are always a big easter egg hunt.

[King Peetis]

Let us know what you learn. It seems cooling fan problems are always a big easter egg hunt.

Most certainly! Once I put all the pieces together I will definitely share. It seems to be a common occurrence for us. If you google "3Geez site: over heating" or "engine cooling" or "cooling fans" the hits are 10 pages deep.

How many sensors, relays, fuses and components make up the engine cooling system?

**Of course the fan and radiator
1. thermostat
2. TW sensor
3. engine cooling sensor (the one next to the TW sensor)
4. engine temp sensor
5. cooling fan relay
6. cooling fan fuse
7. thermoswitch
8. heater core

I think there is another relay...Anything I'm forgetting???

[Dr_Snooz]

The 4g manual has a troubleshooting section for the cooling fans. Too bad it's not accurate. The 3g manual would benefit greatly from something similar. Something accurate, that is.

[King Peetis]

I removed the thermostat and tested it. No problems. I tested a new one that I had around the house and it tested good as well. I swapped it jus cuz. I replaced the O2 sensor cause of the failed carbon monoxide test during the emissions check. I topped off the coolant and then I drove it around to get the temp up. I pulled in the driveway...the heat started to climb...and still no fucking fans!!!! I popped the hood, ripped open the fuse box and stared at the relays. I pushed on all three to make sure they were in all the way and I noticed that one of the two black relays was warm and the other was cold. so I said what the hell and swapped them.

The fans came on.


The sub fan relay is bad (they are both the same anyway) so I'll just replace it. But anyway, that was the issue for the overheating problem; the cooling fan relay.

Oh yea, I passed emissions too btw. Im legal--finally.

[2oodoor]

I removed the thermostat and tested it. No problems. I tested a new one that I had around the house and it tested good as well. I swapped it jus cuz. I replaced the O2 sensor cause of the failed carbon monoxide test during the emissions check. I topped off the coolant and then I drove it around to get the temp up. I pulled in the driveway...the heat started to climb...and still no fucking fans!!!! I popped the hood, ripped open the fuse box and stared at the relays. I pushed on all three to make sure they were in all the way and I noticed that one of the two black relays was warm and the other was cold. so I said what the hell and swapped them.

The fans came on.


The sub fan relay is bad (they are both the same anyway) so I'll just replace it. But anyway, that was the issue for the overheating problem; the cooling fan relay.

Oh yea, I passed emissions too btw. Im legal--finally.

congrats! on both.

I think there is a wiring diagram in the factory manual and in another area there is a component location diagram. I am not sure though if those diargrams cover all the areas associated with the engine fans. If you ever need a wiring diagram I can give you one.

[ecogabriel]

I removed the thermostat and tested it. No problems. I tested a new one that I had around the house and it tested good as well. I swapped it jus cuz. I replaced the O2 sensor cause of the failed carbon monoxide test during the emissions check. I topped off the coolant and then I drove it around to get the temp up. I pulled in the driveway...the heat started to climb...and still no fucking fans!!!! I popped the hood, ripped open the fuse box and stared at the relays. I pushed on all three to make sure they were in all the way and I noticed that one of the two black relays was warm and the other was cold. so I said what the hell and swapped them.

The fans came on.


The sub fan relay is bad (they are both the same anyway) so I'll just replace it. But anyway, that was the issue for the overheating problem; the cooling fan relay.

Oh yea, I passed emissions too btw. Im legal--finally.

Good you figured out what was going on with the fans , and that nothing got broken in the process. Oh, and that you passed emissions!

I do not have to test the car (it is 1986) and it feels kinda strange... but good!

[Dr_Snooz]

Nice work! Thanks for the follow up.

[King Peetis]

congrats! on both.

I think there is a wiring diagram in the factory manual and in another area there is a component location diagram. I am not sure though if those diargrams cover all the areas associated with the engine fans. If you ever need a wiring diagram I can give you one.

Brotha Doo, long time! Yea man thanks! I will take you up on the diagram if its different from the service manual. Can you zip and email it? If not, send me a PM and we can figure it out.

Good you figured out what was going on with the fans , and that nothing got broken in the process. Oh, and that you passed emissions!

I do not have to test the car (it is 1986) and it feels kinda strange... but good!

Lucky you! I have two years to go!

Nice work! Thanks for the follow up.

Theres nothing worse than a fella that spends time on the forum getting advice and says "Thanks guys, I figured it out" without providing the solution...

[Hauntd ca3]

so i was right?

[King Peetis]

remove and test the fan relay.
if the temp switch is known to be good and the fans turn on by jumping the 2 terminals at the switch plug, the relay is quite likely the prob

so i was right?

Is that a rhetorical question? Yes, you were absolutely correct. Shame on me for not listening long ago. Now that I look back I'm not sure why I did not. I'm a parts and pieces; hardware kinda mechanic. I hate electrical related issues so much that I most often don't believe they are to be considered until all parts have been change out. Quite the phsyco-babble coupled with ignorance but the truth nonetheless...oh yea, and thanks again for the advice.