Strange cooling fan issue?
Strange cooling fan issue? Both low spd fans work great but when its time for high spd fans to come on only the driver side fan goes into high spd. The passenger side fan shuts off.
When the driver side is in high spd it will bring down the temp enough to go into low spd settings. Then both fans continue in low spd like normal.
What's up with this any clue?
My fan settings with a 160 t stat...
low spd on 194
low spd off 186
high spd on 198
high spd off 194
When the driver side is in high spd it will bring down the temp enough to go into low spd settings. Then both fans continue in low spd like normal.
What's up with this any clue?
My fan settings with a 160 t stat...
low spd on 194
low spd off 186
high spd on 198
high spd off 194
Thanks guys. I tried switching the #1 and #3 relays to see if any change. No change. Also checked the 2 fuses and they are good.
#2 relay is the conclusion I was coming to. I was just looking at the electrical schematic and it looks like the low spd fan is in series while the high spd is in parallel which includes #2 relay. So it would make sense that #2 relay is probably the bad apple. Ill get a new one and see how it goes.
#2 relay is the conclusion I was coming to. I was just looking at the electrical schematic and it looks like the low spd fan is in series while the high spd is in parallel which includes #2 relay. So it would make sense that #2 relay is probably the bad apple. Ill get a new one and see how it goes.
Last edited by senicalj4579; Jul 8, 2013 at 08:45 PM.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Swapped the fan motors with each other just for the heck of it and no change. Cant be the fan motor.
Looked for obvious wire issues with no luck. Might have to take it somewhere to have the correct wire paths tested. I'm not great at diagrams. Any help would be appreciated.
Looked for obvious wire issues with no luck. Might have to take it somewhere to have the correct wire paths tested. I'm not great at diagrams. Any help would be appreciated.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
If thats the case, it looks like your not getting power to terminal C4 (the red wire) on relay #2. Check that wire for 12V. It could also have 12v with the fans off and then drop to zero when the fan trys to engage. So also check it with a load (the fan) on it.
C4 (red wire to relay #2) has 12+v with fan off and on. Whats next to check?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
That does get a little weird then. Try checking for 12v at pin C6 of fan relay #2, it should always have 12v. If thats not it, try checking for a ground signal at pin B4 of fan relay #2, it should be grounded when the computer is calling for high speed fans. If all that fails, unplug relay #2 and 3 and try putting a jumper wire between terminals C4 and B6 of relay #2 that should make your right fan run full speed. Use a decent size jumper, at least 14 gauge, and it will probably spark as you connect it.
That does get a little weird then. Try checking for 12v at pin C6 of fan relay #2, it should always have 12v. If thats not it, try checking for a ground signal at pin B4 of fan relay #2, it should be grounded when the computer is calling for high speed fans. If all that fails, unplug relay #2 and 3 and try putting a jumper wire between terminals C4 and B6 of relay #2 that should make your right fan run full speed. Use a decent size jumper, at least 14 gauge, and it will probably spark as you connect it.
c4 and c6 both have 12v
I probed B4 with the test lamp. Clamp on +. Commanded high spd fan on. Test lamp did NOT light up. So does this mean for sure its a ground or could it still be something else?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
That sounds like there is a problem with the wire between pin B4 of relay #2 and splice #166, because your PCM is sending a ground signal for high speed to relay #3 but not to relay #2. Trace the wire from pin B4 of relay #2 back towards the PCM and see if you can find a cut, break, or bad splice.
That sounds like there is a problem with the wire between pin B4 of relay #2 and splice #166, because your PCM is sending a ground signal for high speed to relay #3 but not to relay #2. Trace the wire from pin B4 of relay #2 back towards the PCM and see if you can find a cut, break, or bad splice.
This is going to suck lol
I OHMed out #33 in the wire harness to B4 (#2 relay) and then C10 (#3 relay). C10 showed .2 - .5 ohm and B4 showed 0.
I think this confirms what you said G-Body.
Thanks for the help big time. I will begin tracing this dark blue wire.
If anyone has any idea of where the splice is or anything please post.
I think this confirms what you said G-Body.
Thanks for the help big time. I will begin tracing this dark blue wire.
If anyone has any idea of where the splice is or anything please post.
There's no way I'm going to find the damaged wire unless the intake and other things come off the car. It might even be behind the firewall for all I can tell. So I decided to just jump C10 #3 relay with B4 #2 relay. Works great. Thanks for the help G-Body 
