Cooling fans inop....

[RedZMonte]

So i replaced the tranny in my 1994 Z34 Lumina and after the tranny is in, rad., is in and fans are hooked up.. the car runs and drives everything seems fine other then the cooling fas are not working.. Primary and secondary don't turn on at all. they are both pluged in and i wiggled both relays and nothing... engine definaly gets hot enough to be turning them on.. Coolant tems sensor? the temp guage on th dash is working, so i wouldnt think its the temp sensor...

Any suggestions on what i should check first?

S

[pocket-rocket]

The sensor for the ECM (which determines when the fans come on) is different from the one for the gauge in the dash. The one for the dash is the one in the LIM, the one for the ECM is the single wire probe in the drivers side of the front head, so go back and make sure that one is plugged back in. With that one not plugged in though I would imagine you would get a code and it would be a dog from the ECM dumping fuel to make sure the engine stays cool (lean runs hot, rich runs cooler).

[RedZMonte]

its like a green wire or something like that.. i think i know the one which one your talking about.. i will unhook it and make sure its plugged in correctly. Will keep you posted.

Thanks
S

[walterdude]

If I remember, when I forgot to hook up that wire (single wire to the temp sensor) BOTH fans were running and I believe a code was set.....
It's been a LONG time but, I'm pretty sure.....
Good luck,,,,
Tom.....
That car was a 93 Z34---DOHC
If you can verify this it might be a good way (to un-hook that sensor) to trouble shoot... You know both fans "should" be getting juice whenever the key is on,,,, you can probe/check for power from point to point.....
Just a thought...
If everything was working before the tranny job you might want to check real close for a wire (sensor??) that might have gotten pinched/damaged in the process.... That wire does run close to where the trans bolts to the engine....

[RedZMonte]

If I remember, when I forgot to hook up that wire (single wire to the temp sensor) BOTH fans were running and I believe a code was set.....
It's been a LONG time but, I'm pretty sure.....
Good luck,,,,
Tom.....
That car was a 93 Z34---DOHC
If you can verify this it might be a good way (to un-hook that sensor) to trouble shoot... You know both fans "should" be getting juice whenever the key is on,,,, you can probe/check for power from point to point.....
Just a thought...
If everything was working before the tranny job you might want to check real close for a wire (sensor??) that might have gotten pinched/damaged in the process.... That wire does run close to where the trans bolts to the engine....

I will try it. I cant say for sure if they where working before i did the trans. i bought it with a bad tranny.

Can jump the relay to turn the fans on manually? (obviously for diag purposes)

S

[pocket-rocket]

Yes. Also if you do the code pulling paper clip trick, the ECM turns the fan on then too.

[RedZMonte]

Yes. Also if you do the code pulling paper clip trick, the ECM turns the fan on then too.

Good to know. Can you please remind me what pins i need to connect? Lol i havnt had to do the paper clip trick, my monte is a 1995 and my 1992 i didnt have long so i never had to pull a code..

Thanks,
Shane

[pocket-rocket]

The top 2 right ones.



Pic provided by: http://www.extreme-check-engine-ligh...%20Decoder.htm

[bszopi]

Not 100% positive since its a DOHC, but the ability to retrieve codes via the "paperclip trick" on the pushrods was deleted in 1994, when OBD-1.5 came out.

[pocket-rocket]

I thought that started in the W bodies in 95? Ok, Shane, if the sides of the connector are angled (like this: \___/ ) instead of a perfect rectangle, don't shove a paper clip in there.

[bszopi]

My Beretta had the old OBD1 connector, but the wires were not run to it to allow for the diagnostics mode. It is documented in one of my manuals that I have that is stopped with the introduction of the OBD-1.5 system. Like I said, since its a DOHC, I'm not sure...