So I recently purchased a 94 z28. I have had a couple concerns that I have been watching...however, one I can't just watch. The fans will not turn on. I have tried cranking the AC, turning on the rear defrost(I read that somewhere) and no fans ever, even when it hits red, eeek. I wanted to goto the track tomorrow night, but it doesn't look good. Im at school so my access to tools and jacks and crap is prettymuch non-existant until im home in a week. I crawled under the car and saw the fan wires and such, looks like a light and a dark off each fan. Anyway, on the passenger side fan I was checking for a loose connection and the connection fell off in my hand...obviously thats not good. I have 3 relays in my U/H fuse box so I assume its the late 94/ 95 style setup. Does the wiring scheme of this setup have it so that it needs a connection there to complete the loop? If it doesn't than im about to cut the wire down by the fan and hook up a switch under the hood, im that pissed. So please help me, thanks in advance.

-Garret

 

I'd go out and get a Hayne's manual if I were you... It's so helpful when trying to figure this stuff out.

Do not take your car to the track like that- full throttle with the temp gauge in the red will be a good way to blow a gasket.

Anway, I forgot how to test the relays. But another piece of advice is not to hook a manual fan switch up directly to the fan wires- too much load, I blew a switch and had some burnt wires. You have to hook into the relays, basically you run from the relay wires to your switch, switch to ground and you're set- put a light inline with the switch so you can see if current is passing through or not also. I know the wires are very small, one is blue and the other is ???

I think I got all my info from another thread on this site. Your best bet would be to do a search on here, this stuff comes up every once in a while.

Anyway, problem areas could be:

Coolant temp sensor
Relays
Wires- to fan, temp sensor, ecm to relay, etc.

Didn't you say neither fan turns on? Either you have breaks in both your fan wires or it has to be before that.

Good luck.

 

A search didn't give me the info I was looking for, I have been searching all around trying to find stuff.

I don't feel like its an issue with the coolent temp sensor because I understand that with the rear defrost and AC on both fans should be on.

Thanks for the help and info, anyone else feel free to add though

thanks.

 

BTW, I wouldn't dream of driving it at the track with this problem...thats why I want to take care of it by tomorrow evening

So just for testing purposes, how can I wire the fan through the relay to a switch the EASIEST way...just to test, thanks.

 

what would happen if u wire it directly to the fans

 

is the compressor coming on when the AC is on? the fans will come on with pressure in the AC system. if the AC isn;t working they will not come on.

 

Turning on the rear defrost does not have anything to do with the cooling fans. The a/c does, though.

Can you read a schematic? Your system will be like the lower part of the diagram.

Have you tried swapping out any of your relays? You can use the fog lamp relay and swap them one at a time and see if they work. There are all kinds of testing tips on my Tech Page.

If you want to easily test through most of the wiring and the relays, locate connector C100 (from the schematic). On a 1994 it should be near the RH hood strut mount. On later cars it is on the RH shock tower, next to another connector. You are looking for the connector with the green and blue fan relay wires in cavities "J" and "H". Unplug it and use a jumper to ground touched to the green wire to run the low speed fans (key must be ON and jumper to the harness side going toward the front of the car). Jumper both green and blue to ground to run high speed fans.

If you want to test that each individual fan will run, you can pull relays 1 or 2 and jumper pins 1 and 4 in the relay socket (key does not have to be ON). If you can read the schematic, you probably already figured this out.