Here are some pictures to help you diagnose your cooling problems. At the very least, it's a handy way to learn how the system works.

 

I found this post very helpful in trying to un-rig my radiator fans. The previous owner had them setup to run whenever the ignition was on. I'm using chart C-12 to try to figure out why neither of the signal wires are grounding the relays to turn the fans on. The chart refers to a diagnostic test port as well as multiple circuits, but I'm not sure where they are. is there another page you could scan that lists their location? Also, what book are you taking this from? I think I'd very much like to have it.

Thanks
Justin

edit: also, I can't find my A/C Pressure Fan Switch, it's not in the location shown near the top of this page. Any help finding it along with the sensor that tells the ECM the coolant temp on an 88' 5.7L IROC (i've read that it's somewhere around the thermostat and it's three wires.) would be great.

 

That is a good piece of info for troubleshooting.IROCWPB it looks to be out of a Camaro/Firebird factory service manual or TSB because of the date in the lower right corner

 

I wanna know exactly what it is because it seems it's written for idiots like me I have alot of un-rigging to do in this car between the electrical and the A/C.

 

Hi guys, I saved these pages off another message board quite some time ago. It was from a guy with a 1991 model.

At the time I was trying to figure out when and why the 2nd fan turns on. Mine had never turned on even after sitting in traffic for 30 minutes in the summer. (Turns out the car just wasn't getting hot enough to turn it on)

I don't think I have any more pages. I'll look when I get back home from the holidays.

 

I have narrowed it down to being a "GM Service Manual" "Carline Manual" or "Helms Manual" lol

I did some googleing and three different forums called it three different names. I think Helms might be reprinting the factory manual though, not sure where Carline comes from though, although the sheets above do say carline on them.

 

I believe the "Carline" referred to on the pages is meant as "F" Body Carline.

 

This should be a sticky.

 

Could someone post the voltages at the relays with the ignition on, engine off, cold car?

my green/white wire (primary relay signal) has 0v
my gray wire (secondary relay signal) has 7.5v
my brown wire (ignition power i guess) has 12v

is something wrong here? why would i be getting 7.5v? I'm trying to diagnose why only one fan will run while they're both hooked up, but either will run if the other is unplugged at the relay.

edit: also, where's the bulkhead connector (G8) supposed to be? I honestly don't even know what a bulkhead connector is, but there's no brown wire running up my frame rail for me to follow.

 

I hooked both relays up to the green/white signal wire and everything is working great now. Still not sure why the secondary fan's signal wire has 7.5v on it. Although now my fans are coming on very early, like before 160* which I don't mind one bit, I just have to put a lower temp thermostat in it and I'll probably drill it.

 

That's definetly from the factory service manual.
That's referring to the C100 bulkhead connector, the big honkin thing with all the wires running to/from it under the fan relays on the driverside firewall. G8 is the location of the brown wire... think of a grid made up of rows A-G and columns 1-8

 

Does anyone know the name of the wire/cable that runs from the radiator to the end of the motor block (left side?)

 

this should be stickied

 

Yes thats factory service manual. I have one and I am just now learning to reap the benefits. Got it and the electric diagnosis for like 40 bucks on ebay.

 

Best thing I ever bought, I got it right after I got the car and it has info for just about anything

 

quick question here, i have deleted the AC out of my car and all the wire connectors are hidden from water (not plugged in), did i just basically kill any chance of the secondary coming on? or is there a secondary system that comes on even with out the AC? i know that the relay is probably shot but just wanted to ask first before getting a new relay

 

Even with no A/C, it should still turn on when the passenger head fan switch gets to the turn on temperature. A 1LE car for example would still have the passenger fan turn on when the coolant temp gets to 235°F, assuming everything is stock.

Now in Ontario in late September, your chances of the car getting to 235° are slim to none. So your fan will appear to not work. But in reality it will work if the car ever does get up that hot.

 

how the heck did you know i was from Ontario?? lol hehe well it hasn't worked all summer, so i'm assuming that the relay is shot(maybe), hasn't been replaced in a while, could also be the temp switch has gone bye bye, should have had it replaced when i did the coolant flush last year :P oh well next time

 

Sorry to bring this old thread up again but this should be a sticky.

I vote sticky it, it has helped me out and will answer a lot of peoples questions.

 

I am not sorry to bring this thread up again. It helped me out tons today. I have been trouble shooting my fans for a little while, and then came across this. What was confusing me is:

I bought a new fan switch and it still didn't make the passenger fan come on. The primary/drivers fan would come on at about 245 and it took a long time to shut off. The secondary fan would never come on. I fired up my turkey cooker and bought another new fan switch and placed in in some antifreeze and proceeded to heat it until I could not heat it any more. Sure enough, with everything grounded and the wire going to the switch with another length of wire, the secondary fan would kick on. I thought yeah, this switch is working. I installed it into the car and fired it up, still would not kick on the secondary fan even at over 250 degrees on the gage. I searched on here again and found this thread. Wow, how easy to trouble shoot it. This got me to thinking maybe my gage is reading wrong?!?! What a thought. I shoved my turkey thermometer into my heater hose coming out of the intake and proceeded to compare the values. at first the turkey thermometer was about 35 degrees higher than the gage in the car. This is bad I thought. I let the car idle a little while longer and the thermostat was opening at 160, I thought, but when it opened the turkey thermometer said 202, and my gage in the car said just a little over 160. I let it idle a little longer and the turkey gage finally started to rise slowly and was getting near 215 when the cars gage somewhat quickly jumped to 230. I guess I always missed this because I was driving. When the turkey gage hit 215 the primary fan kicked on and started cooling it just fine. The gage in the car was over 245 at this point. I unplugged the relay for the primary fan and let it warm up even more. At 225 on the turkey gage the secondary fan kicked on and everything was great. The cars gage was over 260 at that point.

I if I hadn't seen this thread I would have never second guessed my gage. I never thought the gage could be wrong like that, especially since it seems to travel the entire range and it has been kicking my butt for a while. Hopefully this will help someone.

 

Hi 87 here. The driver side does not come on and the passenger one is on all the time. I turn on AC and only passenger one. Ac spikes temp to overheating. Based on everything i read i need to check ac feon?
Help

 

Did you ground the diagnostic terminal on your ALDL? It is the second one to the left on the top row. Run a wire from it to a ground and Turn on your key. I use the seat bolt on the floorboard. If this doesnt kick on your Primary fan/driverside nothing will. This means something it either wrong with your wires, fan relay or the Computer. I would try the relay first, they have been known to go bad. Secondary fan being on all the time sounds like the Fan switch on the passenger head has beed grounded permanantly.

 

What is ALDL?

 

It is the old name for the diagnostics port. They call it an obd1 or obd2 port now.

 

Help one fan work all the time.. pass side... the driver side fan didnt work at all....
I flushed the radiator yesaterday and now no cooling fan works. What do I do....manual says put a iwre in the d and e and see what happned what is where is the A and e.. you get my drift!!!@

 

is it a seperate scanner? or is it internal through the check engine light?
The manual seems helpfull
only if I knew what the scan tool was and how it works?

 

This is EXACTLY what my 91Z is doing. I replaced the sender, switch, and sensor, did every check specified in these threads and then some, and my gauge still pegs out before the primary fan turns on. What did you do about the gauge? Send me a pm if you wish. Wouldn't want to jack the thread. Thanks.

 

hi, you seem to be THE person to talk to,,,, i have an 86 trans am , i dropped a built 355 tpi in there, with a aluminum 3 row rad, the ecm and wiring is from a 87 iroc, i deleted the a/c, even the heater, only gonna drive in summer when weather is good. now my question,, i dont have dual fans in the car i have the stock 86 single fan, since i dont have a/c , and i deleted half the harness to have only one relay to my fan,,,, now what should i use to trigger that single fan? i have, 1. the stock temp switch on pass head,2.a temp switch on my new rad 3. the ecm that takes the info from that temp switch on the intake below throttle body, can i use the gre/wh wire from the ecm and both switches on the same relay?? should i rely only on ecm? only on 1 switch? 2 switches? if i use the ecm at all,,,, since i have an 87 wiring, do i ground, or open the blue wire from the a/c? cause i dont have a/c ,,,the car i took the ecm and wire from used to have a/c. if i dont use the ecm,, can i just leave it like that or is there something i should change not to mess up anything,,,,,, i just dont wanna try a bunch of things, want to wire the car properly once,, and hide harness with loom once and for all,thanks.sorry for the looooong question

 

Hey man what's up, were did you get this info is this from a No **** 92 camero mechanic repair manual, and if so were did you buy it.Thanks man

 

Could just be me, by FYSA, I don't see ANY diagrams in the 1st post. Just some SPAM crap to install some App.

 

Same here I came here for this thread for my cooling issue but its just an ad for Itunes??

Could we make it a sticky or repost.