I posted a while back about my 89 gta fans not working .I since then replaced both fan relays and the fan turn on switch in the motor and a new wire to the new switch .. A new coolant temp sensor and thermostat And My fans wont come on at all I tried to jump the big connectors on the relay and nothing I turned on the ac and no fan The car will idle itself past 250 at idle .Can someone tell me where the fan ground wires are . I hooked up 12 volts to the fans and they both work .Would me welding in sfc's fry something .I am at a total loss here I want to get it registered this week so I can enjoy some of whats left of this wheather .Any info is greatly appreciated ....Thanks.......

 

well when welding, i was told to unhook the battery but, anyway.

https://www.thirdgen.org/techbb2/sho...al+fan+diagram

in that diagram u see a fuse being listed in the circuit, did u check that?

in this diagram you see the basic layout of what voltages are where.

 

I checked the fuse and looked at everything and it all seems in order .My car sat for about 8 months udergoing retoration. I Welded in some new sheetmetal and sfc's .But I did'nt unhook the battery .I also changed the battery terminals .I read in a post a while back that the ecm could run the fans .Being an 89 it is different than my old iroc and I am confused .Before being on blocks the car ran fine .No problems at all . I pulled it out of the shop and the fans have'nt worked since . I also rewelded in new chassis top rails in .I pulled all of the wires and I think they are all put back .(no loose wires) I am dumbfounded at this point The car is 94% ready to go through new inspections but it wont switch on the fans .Anyone here fry an ecm before ?? is this a symtom?? Help please........

 

even if the ecm was fried, the secondary fan should come on at the higher temp way before the 250 mentioned.

the secondary fan should come on through the fan switch, which grounds the relay giving power to the fan when the car is on.

the drivers side fan sohuld come on first, and that works with the coolant temp sensor which at the certain temp te ecm reads and turn on that fan by grounding out the relay.

so it seems like u said maybe the fans are not grounded right, there should be two wires going to the fan connections, one has to be hot the other is has to be ground.

i would try and trace down the ground wires for each fan and make sure they are properly grounded.

 

Ok I traced down the wires that come off of the fan They are grounded by the headlight .Is There any grounds for the relays I can;t find them . Anyone know where they are and if they are inside the car or in engine bay ? Thanks in advance...........

 

Connector F on the relay is the relay coil ground, it should be green. This isnt the ground for the fans though just the relay. I beleive the coil ground runs to somewhere around the AC compressor, to a pressure sending unit, and elsewhere as well depends on which relay (primary or secondary).

Im not sure exactly what you've done to test the fans so i'll run through it like this.

Step 1) turn ignition on and jump A (black/red) to E (orange/white) pins on the relay.
if fan DOES run, skip to step 5

Step 2) If fan does not run hook fan directly to battery.
If fan still doesnt run, buy new fan. It's shot.

Step 3) If it does run, trace the black/red wire from the fan to the relay and test continuity (make sure the wire isnt broken somehow). Trace the solid black wire from the fan to a ground connection on the body right next to the relays, and again check for a good ground connection and continuity in the wire.

Step 4) if all those wires are good, trace E (orange/white) all the way to the battery, make sure it has power. (errr, on my car at least, yours might run to a fuse or to the ignition, but that wire needs power somewhere). You see all the relay does is switch power from the orange (E) to the red (A), If jumping these does not work your problem is in either your fan, E, A, or your ground wire.

Step 5) Consider possibility of a bad relay. The relay should switch E to A when current runs through D to F. To test these, test continuity on F with the car body (ground) or even just jump F to ground and see if the fan turns on. See....I'm not sure if it's a switched ground or a switched hot.....Probably switched ground, which means you should test voltage on the hot (D) all the time and be able to trace it back to the battery, if i'm right about that, jumping F to ground, either the fan will run, you've skipped steps, or the relay is bad. If F is in fact constant ground with D being switched.....I dunno where that goes....Anyone else?

Step 6) If jumping F to ground turns the fan on, (and i'm right about the ground being switched) Either you've got a break in that wire or basically, all the things which would switch it to ground are broke (things that might include AC pressure switch, temp. sensor unit, ECM, uh...Thats all i know of).

I've lost track of what i'm even typing here trying to picture this in my head heh but i think that runs you through a complete diagnostic of everything in the fan circut, save for the 'switches' like the ECM and the temp sensor...but those -probably- arent your prob....odd that they'd ALL be broken. Hope this helps..

 

Dude thanks alot for the great info . I ran power to both fans and they work .I peeled all of the outsde wire gaurds and all my wires are exposed . I found that in the ac switch wire was spliced and the orange relay wires are spliced together . I also found that on the neg battery cable there is a little round rubber grommet that has a fusable link on it and in the back of it there is an orange wire coming out of it .But this wire has been cut and a new wire was soldered in to hook up to the orange wire on the pos side cable . I am sure that the previos owner rewired the fans somehow and I think that they are turned on by the ac pressure switch ?? I have no pressure in the ac at all .Could this be why the fans arent switching on?? Would ac pressure not turn on fans?? I replaced both relays and new temp witch and switch in motor between 6-8 cylinder The car ran fine before I parked it and the ac was never recharged . I will try to bring it back to stock setup somehow .Thanks again.....