Got a strange code 77, both my fans are good and so are the relays. I got a CEL on and got it scanned today with a code 77 fans system 1??? They don't even turn on when the AC turns on.

Please, I don't want to rig this up. Thanks!!

 

The code includes the relay circuits. If the relays check out ok, then maybe the circuits are not.

 

Its the God of LT1s! So glad you posted Thanks!

I had a buddy put it on a Tech 1 and he couldn't get the fans to turn on with it. Yet I checked the bye pass on each with hard wire and they both work. So its not a fan motor issue. I just pulled the LT1 in the garage and was going to check the wiring under the fuse box. I don't think its there but worth a try. I have a back up PCM that I may try, just to check the PCM. It could be wiring. I've done nothing to the car for it to all of the sudden not work. I maybe put 150miles a month on it. I've swapped the relay on the AC which I KNOW works and still nothing. From my understanding There is nothing in the middle from the pcm and the relay. So it may be wire or PCM.

Thoughts?

 

FOUND IT! Bad connection under the fuse box on the fuse. So glad I found it. Now I wish I could start it to check but its too late.

 

Ground the diagnostic terminals on the DLC with the key ON (like you would flash codes on an earlier car) to see if your fans will run. The engine does not have to run. (it won't flash any codes on a 1994)

http://shbox.com/1/dlc2.jpg

 

I thought this was it. Fuse burned up when I started it. However I found it had 17 volts at the fuse? So I went to the Bat and it had 17 too but it fluctuated 11-18 volts! So to me it sounds like the Alt volt reg is out? So I need to swap the alt....

 

Shoebox, Just sent you an email. I need to trace the brown wire under the fan fuse. The wire is grounded and I'll need to replce the wire to the PCM. Thanks!!

 

Since you have access to a Tech 1, this may help you:



Good luck!

 

In my email to you I indicate the brown wire does not go to the PCM. It powers many things that include:

fan relays
O2 sensors
reverse lockout
skip shift
EVAP solenoid
EGR solenoid

The brown wire feeds through the forward harness to the RH shock tower and through C100, cavity F, then on to the items listed above.
If you unplug C100 and your ground goes away, then you can concentrate on the harness from that point on and/or the things listed above.