I have had the ls1 fans on miy truck for like maybe two years and they havent ever had any real problems ive had a relay go bad but thats about it. well the other night i was messing around with it fixing to do another cam swap before i put all the new stuff in and i noticed the fans wasnt working then smoke came out of the little red battery box. i took that apart and saw that one of the wires had rubbed into so i cliped the ends off and and put new connectors on and fixed that. well my fan will come on with the a/c and the same fan will kick on high when the truck gets warm...the other fan will not come on at all. i checked all the wiring and checked all the realys and they are all good. I even threw another set of ls1 fans in there just to make sure that fan wasnt bad and still nothing... im at a los on this i suck at electrical anything but as far as i can tell everything is good and i took as much of the harness i can apart and everything looks good. any ideas?

also i have a blue and green wire that go into the pcm wich one control wich fan... i dont remember wich pins they were. its justins harness on a 04 truck


any help is greatly appreciated
thanx,
garrett

 

Which fan comes on? Driver(fan1) or passenger(fan2) side fan? Is this a 2-relay or 3-relay setup?


How did you check the relays. did you energize them? did you check for continuity?

sounds like he used the stock colors. blue would be the trigger fan1, green fan2, hopefully.

 

Passenger fan 2 is the one that's working. Its on a 3relay setup and to check them while the fan was running I unplugged the one that was running the fan and put the onther two in the same spot and they all worked the fan... Some maf clean and spray out the plugs where they plug in just to make sure they are clean cuz I can't think of anything else

 

If fan1 is not coming on then I would think either the fuse for fan1 is bad or the motor for fan1 is no good. But with either of those symptoms, fan2 should not be coming on with the temp trigger.

Fan2 should only be coming on with the a/c and it should be on high.

If you can, swap the fan connectors: fan2 to fan1 and fan1 to fan2. See if fan1 runs with the a/c. This will tell you if the motor is good or bad.

Check the fuses.

What's bothering me is that you say the fan comes on because of temps. If the temp triggers and the a/c is not triggered, then the fans are running in series. So, if something is bad: relay, fuse, motor, then both fans will NOT run due to a break in the circuit. If everything is good, then both fans run at a lower speed (due to the reduced voltage of the series setup).

 

Thanx man I will try it.. I got it tore apart right now swapping a diff cam in. Where are the fuses for them? There's not any fuses in the harness just relays are there's fuses in the fuse box ?

 

Hey- I gotta chime in here. I'm having some issues, too. My fans don't run anymore bit when I touch the signal wire to the battery+ I hear a clicking, but the fans don't turn. Just glad I live in a rural area with minimal stop and go driving.......

 

are there any fuses in the system? theres none in the harness but mine will not come on at all now and i have check everything and they wont do anything.... im fixing to throw the clutch fan back on and be done with it and maybe later go to the 34" rad and oem fans

 

Isn't it Blue 42 & Green 33? I'm goin from memory, so correct me if I'm wrong. All these stories about bad fan relays are starting to concern me.

 

SO what was the fix bumpers? I'm having the same issues right now after putting this engine bay all back together. The fans have worked fine in the past...

When you start the truck, SOMETIMES the pass fan will come on for half a second, then go off. It should come on low if I'm not mistaken until I turn the A/C on or it reaches temp. It never kicks on when it reaches temp. It will only run when the A/C is on. It will come on high with the A/C compressor, so I know thats still right. The driver side fan wont come on at all. I'm about to go try and swap connectors and see what that does, and also swap relays.

Just figured I'd ask since my problems are exactly the same as you described. Ive checked the pin 42 wire, its good, checked the A/C wire, its good, the grounds are good and the hots are good.....was wondering about fuses? Like you said there are none on the harness....

Some closure on your problem (if you have any) would be nice!

 

Well ok I just went out and switched the connectors.....started the truck up, now the DRIVERS side fan came on upon start up for like 5 sec, then stops. Turn the A/C on, the Drivers side fan comes on now instead of the pass.


So that tells me the motors are good.

I left the A/C on, and pulled the relays till I found the one that controlled that fan. I swapped one in its place, worked great, but swapped another in its place and it didnt work.

So now I'm assuming that relay is bad......could that one relay being bad be the source of my problems?