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quick question/double check on fan relay wiring for 1994 lt-1.
long story short, the PO “wired the fans to be on always” I assumed he had done it via triggering the relays to be on. However, he actually just routed a power wire straight from the ignition switch to the fans, ie the ignition switch was powering the fans, no fuses. This resulted in the ignition switch partially melting and sticking to the ignition rod.
I’m trying to go back to stock, looking at the fan relays, the attached picture id what I found.
I have connected blue to blue, red to red and the two smaller red wires to the smaller red wires.
my understanding is that the dark blue and dark green are the relay trigger wires right? If I wanted to have a manual override switch I should ground those two wires.
anyone agree or disagree to what I got?
thanks
Not sure of color used on your year but relay is standard. Computer provides ground. You can provide alternate ground and run fans. I can tell you that secondary ground switch will set a code on a 1992 model but not set check engine light. I have made that mod before and included an LEDs so I could tell when computer turned them on
I believe you need to go back and confirm all of the wiring and components using the FSM. There's 3 fuses involved and then the wiring to relays. I believe I saw snapshots you posted that seemed to not be what I saw in a '94 FSM. I believe I mentioned it then to you. I'd say you need to start over and confirm all. Did you get the steering column ignition switch, rack & rod already sorted? How did the column go?
I believe you need to go back and confirm all of the wiring and components using the FSM. There's 3 fuses involved and then the wiring to relays. I believe I saw snapshots you posted that seemed to not be what I saw in a '94 FSM. I believe I mentioned it then to you. I'd say you need to start over and confirm all. Did you get the steering column ignition switch, rack & rod already sorted? How did the column go?
I’ll dig into the FSM, I do have one. I know you mentioned the under hood fuse block looked off, but it did seem to line up with the sticker on the backside of the cover. I replaced the 30 amp fuse that was jumpered for primary fan.
The column is almost fully back together, my HVAC went out last week so that’s been a distraction. But I pretty much just have lock plate/air bag and under dash covers left.
new ignition switch, new connector, cylinder rotates smoothly. easy day.
i have to say I don’t understand what the PO was accomplishing with the blue to red and cutting the smaller red wires. But when/if I find a good diagram I’ll follow up here
You're missing a relay. There are supposed to be 3 relays on a 94-96. In a 94-96 both fans run in Low speed, then both run in High speed. << Not in 94 according to the FSM guru.
The splice of red to blue is where the relay was removed.The splice of red and blue would power fan 1 at all times. So the fuse for this circuit was where the current from the ignition switch was applied?The relay with 2 large black wires is controlling the Left fan. I don't see that either relay has its pink connected to pink from the car. "Fan' fuse 29. The relays won't work until the pinks are connected.
You can run 2 relays instead of 3, one for each fan. They will both run at high speed, first one, then both. The small green wire is Fan 1, the small dk blue wire is Fan 2. The ECM leaves Fan 1 on when it turns Fan 2 on.
That wiring is a mess. You're going to have to be able to read and understand the FSM schematic to sort it out. Regardless of which way 2 or 3 relays you do it.
You're missing a relay. There are supposed to be 3 relays on a 94-96. In a 94-96 both fans run in Low speed, then both run in High speed.
The splice of red to blue is where the relay was removed. The relay with 2 large black wires is controlling the Left fan. I don't see that either relay has its pink connected to pink from the car. "Fan' fuse 29. The relays won't work until the pinks are connected.
You can run 2 relays instead of 3, one for each fan. They will both run at high speed, first one, then both. The small green wire is Fan 1, the small dk blue wire is Fan 2. The ECM leaves Fan 1 on when it turns Fan 2 on.
That wiring is a mess. You're going to have to be able to read and understand the FSM schematic to sort it out. Regardless of which way 2 or 3 relays you do it.
I don't believe that a '94 is a 3 relay system. FSM displays only 2 (primary and secondary) similar to what's displayed by the OP and should be mounted on the driver side of the upper cooling module support. The FSM displays them at 8A-201-0. Wiring is 8A-31-0 for VIN P.
I don't believe that a '94 is a 3 relay system. FSM displays only 2 (primary and secondary) similar to what's displayed by the OP and should be mounted on the driver side of the upper cooling module support. The FSM displays them at 8A-201-0. Wiring is 8A-31-0 for VIN P.
if you’re ever in SC let me know, I owe you a beer lol
i don’t know if it’s me or my computer, but my FSM isn’t searchable, and the table of contents only goes so far.
Thanks for the 8A-31-0, I found the wiring. Based on my figuring, the primary fan relay was bypassed entirely(red to blue) and the signal wire was cut(small pink) but also, the secondary relay was untouched but it’s small pink was also cut.
So it’s unlikely my secondary fan worked at all.
I think I mentioned it in the other thread, but that “how to GM steering column” link was extremely helpful in understanding how the car is setup.
From what i understand the 94 is an odd ball year which could have been wired with either 2 or 3 relays. Either both fans low speed-both high speed, or, one fan for low and both fans for high.
Maybe the 94 Corvette was only produced with a two relay system. The F body in early production 94 was two relay and the later 94 was a three relay. Even if the 94 Corvette was not a 3 relay, it can still be modified to such. If the wiring is a mess and needs to be redone, its worth considering.
From what i understand the 94 is an odd ball year which could have been wired with either 2 or 3 relays. Either both fans low speed-both high speed, or, one fan for low and both fans for high.
Originally Posted by IHBD
I recall seeing 94s with 3 relays. Learn something every day. I modified the post for the possibility that the OP's 94 was a 2-relay system..
@JD1964 is yours a 2 or 3?
I'll rely on what the FSM displays until I'm shown a '94 with 3 relay system.
I'll rely on what the FSM displays until I'm shown a '94 with 3 relay system.
My C4 Corvette is a 96 so its not applicable here. However, I previously bought a 94 Z28. It was a late production 94 and it has the three relay system.
My C4 Corvette is a 96 so its not applicable here. However, I previously bought a 94 Z28. It was a late production 94 and it has the three relay system.
Your Camaro ain't a C4 so what you found there isn't actually a contribution.
Your Camaro ain't a C4 so what you found there isn't actually a contribution.
I disagree because any 94 or 95 Corvette with two relay system can be modified for a three relay setup. The wiring diagram I linked can be used to do that. In my opinion, some people might find the information useful. I think the three relay setup is better.
94-95 Corvette and Camaro use identical PCM’s, although the tune data might not be identical, the hardware is.
Any 94 that is a two relay from the factory can be rewired using three relays.
Based on my testing of my 90 LT5 and my 92 LT1, any 90-94 can be re-wired to the 3-relay, 2-speed fan set up.
In both of my cars, Fan1 remains energized when Fan2 is commanded, so the 3-relay configuration would work. I don't recall testing which fan is commanded by the A/C fan request. One should verify that Fan 2 is what is requested for A/C as you want the maximum airflow possible, especially with R-134 conversions. (WVZR: This why I thought 94 had 2-speed fans. 94 was first year of R-134 and parallel flow condensers. I thought there was an association between minimizing fan noise, and establishing condenser airflow across the entire surface of the parallel flow condenser. Cheers.)
I really appreciate everyone who chimed in and providing wiring/thoughts.
I rewired the relays back to stock.
Finally got the car started again from its ignition issue.
Let the car run, temp climbed to 228 fan turned on. At 217 fan turned off.
i also wired in an override switch that I’ll mount under the dash. Tested it and both fans turned on when switched(I just routed a the dark blue and green signal wires to ground via switch)
one thing I did notice is that when AC is turned on max, neither fan turned on. Only when temp hit 228 did a fan start. But if that’s the only fault I can live with that.
I am surprised that both relays work. There is nothing wrong with them. Why someone would bypass them entirely and power the primary fan directly from the ignition switch is beyond me.
also due to their bad understanding of wiring, the secondary fan had not been run in a long time.
when it kicked on a bunch of dust shot back over the engine.
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1994 fan relay wiring
