Help! Aux Fan Not Working

[vdogamr]

So I think I am having a very similar problem. I intend to install the lower temperature fan switch but for now I think I have a much bigger problem.

While sitting in a line of traffic, my car's coolant temp got up to 250 degrees and the oil temp got up to 230. I didn't notice any fans kicking on and I couldn't figure out any heater settings to help. So I just did a U-turn and got the car moving. When it moves it stays in the 190s. Do you think fuses are likely my problem? I will be checking my fuses soon, just in case. I removed the fan engineblock-side of the radiator and tested it. It worked fine.

Just to be clear 250 is too high, correct?

Update:
The fuse was fine. I tried to follow the page of the Haynes manual someone posted in another thread to diagnose the problem. (I also ordered a manual for myself) Grounding the switch connection did not turn on the fan (assuming I properly grounded the right thing, which I am pretty sure I did), and I could not find the relay that I was supposed to test. I did find what I assumed to be the relay next to the fan itself, but didn't understand how to properly jump it (I didn't try for fear I would fry something).

 

[woodpuppy]

Sorry for not responding sooner, but I haven't checked email in a few days. My problem was just as you described with the main fan and by replacing all of my fuses it fixed the problem. Not sure what the problem was because all of the fuses were good, but I had tried everything else and the fuses just looked old so I decided what the heck it only cost a few dollars to replace them and it can't hurt.

I also replaced the thermo switch on the left side of the engine that runs the aux fans.

There are numerous schools of thoughts on the whole temperature issue, but for me I prefer having the temps run lower even if they are designed to run around 220-230 degrees.

Coolant temp of 250 degrees and oil temp of 230 degrees are too hot.

I'd probable go ahead and change the oil as well after it has gotten that hot it may not offer the protection and lubrication that it should.

Also check between the radiator and ac condenser to make sure there isn't a bunch of garbage in there restricting air flow.

I'd have to go back and look at my old post, but I'm pretty sure i documented it pretty well, so if you search for my post by user name "woodpuppy" you'll find the steps I took to solve my problem in case I forgot to mention it here.

Good luck!

 

[vdogamr]

I believe I did get an oil change the day after that (if not earlier that same day :confused). Not that I knew I should, I had just been meaning to and I had a coupon. I replaced my cooling fan fuse because it looked old as well. It was difficult to get seated right so I kept trying until some gunk fell out (looked like rust). I am hoping that helped and wasn't the start of a bigger problem. I have yet to change my fan switch, and I haven't had a chance to let the car idle to test the new fuse yet. My guess is that it is still broken. But I am going to fix it.

I will search for your posts now, but do you know how to properly test the relay on an 88?

Thanks

 

[woodpuppy]

Sorry I don't know how to check the relay. Put out a post asking for help and you'll get it. Or reach out to Hib Halverson, VetteFan87, or GM???? it's GM something, I just don't remember right now, but all three of them are very knowledgeable and helpful.

 

[87vettevert]

Sorry I don't know how to check the relay. Put out a post asking for help and you'll get it. Or reach out to Hib Halverson, VetteFan87, or GM???? it's GM something, I just don't remember right now, but all three of them are very knowledgeable and helpful.

GMJUNKIE

 

[vetteoz]

do you know how to properly test the

At work so don't have colors. Find the fan relay and ground the terminal that has the small black wire on it.If relay working it should click and fan start. Touch the two large wires on the relay together and see if fan runs. This proves you have 12V power available to run fans