Hey guys, I've been working on my buddy's 97 Z for the last 2 weeks.


The problem is.....neither of the radiator fans are working. Not even when I kick the ac compressor on. I have tested the tempature sensor in the water pump, and according to the table I got off the net, the Ohm readings are good.

I have hard wired the fans via a jumper in the relay sockets, and they work fine. I'm at a loss as to what it could be. Can you guys give me some ideas to track down?


Thanks....Mike

 

Did you try activating the fans via the ECU (via the DLC) yet?

You can do this by putting the car into field service mode, and then turning the ignition switch to ON, but not starting the car. You have to keep the pins on the DLC connected while you do this. If everything is working, the fans should come on, and they'll stay on until you disconnect the jump between the two pins on the DLC.

If the ECU can enable your fans, then wire somewhere on the way to the ecu might be bad, or not hooked up. Normally, the ecu would enable the fans past 226 degrees. Also, it would enable them while the AC was running, as you seem to know. If the ecu can't turn on the fans in field service mode, then you can be pretty sure that the problem is in the wiring between the ECU and the fan relay.

Btw, did you test the fan relay, or did you just hardwire it across the relay connections? If you haven't tested the relay yet, I'd test that first. Just try one of the other relays which you are sure works; they're all the same (aside from the abs one).

Edit: I just noticed that you said "have hard wired the fans via a jumper in the relay sockets".. sounds like you didn't test the relay.. I'd bet the relay is probably bad..

You can get more in-depth instructions and diagrams of the DLC pinouts, and everything i've talked about in this post on shbox:

DLC Photo

http://shbox.com/1/4th_gen_tech2.html#cooling

Then scroll to "~Fans are not operational at any time~

Good luck! (I had to do this just the other day)

 

yea, Iv'e tested the relays. Iv'e even swapped em around like you mentioned. I've also tried jumping the dlc connector. I got to thinking, could a ground at the ecm be bad? If so, I would think that the car would'nt run at all. thanks.

 

I had the same problem on my 96 earlier this year. the ecu was bad. I replaced it with a used one i got from pcm for less. now the fans work like a champ. if you have chased all the wires and relays the ecu is more than likley the problem.

 

Check your fuses. I think they run off of #6 under the hood.

 

already done the fuse route. I'll look in to the pcm. I'll let you know what happens. Mike