2000 Silverado E-Fan Question...

[GAMEOVER]

I installed an 18" Electric fan on a 2000 Silverado 5.3ltr 4WD. I wired up a relay and used pin #42 on PCM blue connector. I know pin #42 supplies the ground to turn on relay....In the tune I made changes so fan will turn on! But as soon as I start the truck the fan click's on and stay's on. I changed the turn on/off temps, switched to series parallel fans and then to back to auxiliary fan...
In the scan tool under DVT controls I activate the cooling fan setting and the fan turns off. Weird!!! I can turn on and off the fan while under DVT controls... But as soon as I de-activate the fans turn on again...!!! Anyone know why the fan is staying on? Should I try pin 33 on red connector? This is a first for me.....Will post up tune file.....

Thanks in advance!

[GAMEOVER]

Anyone?

[Aloicious]

Anyone?

is this a mark VIII 2 speed fan by any chance?

it sounds like a wiring issue to me.

if it helps, here is the schematic I used for my Mark VIII fan, its a single 18" 2 speed fan, I have it tuned as low speed is fan #1 programming, and fan #2 is high speed. using series/parallel settings IIRC. I'm not at my tuning computer at the moment. the diodes, LED(s), and maual override switch aren't required, but they are optional. I also didn't draw them in, but the power lines should be fused for safety.

if you're not using a 2 speed fan, you can wire it the same as the low speed side, just pull your 12v switched to pin 85 on the low relay and ignore all the high speed stuff.

[GAMEOVER]

I have it wired just like your low speed diagram, except 85 is wired to Pin #42 for negative trigger from PCM, and 86 is wired to 12 volts.
The fan is a Jegs or summit 18" 1 speed fan... I'm trying to find out why the PCM is triggering the Fan on on start-up and doesn't turn off. It just stays on.... Maybe it's something in the tune that Im overlooking....

[Aloicious]

I have it wired just like your low speed diagram, except 85 is wired to Pin #42 for negative trigger from PCM, and 86 is wired to 12 volts.
The fan is a Jegs or summit 18" 1 speed fan... I'm trying to find out why the PCM is triggering the Fan on on start-up and doesn't turn off. It just stays on.... Maybe it's something in the tune that Im overlooking....

hmm...I can't take a look at it right now, but I'll try later.

[Chevy366]

I think 30 should be (+) to fan and 87 battery (+) . 30 at rest contacts 87a , triggered 87 .

[Aloicious]

I think 30 should be (+) to fan and 87 battery (+) . 30 at rest contacts 87a , triggered 87 .

it doesn't matter if 87a isn't used.

[GAMEOVER]

I'm using a 4 pin relay... I'm 99% sure Battery goes to 30 and fan + goes to 87 and since it's negative trigger(PCM pin #42) 85 goes to pin #42..... 86 any 12+ volt source
Maybe it needs to be a 0411 PCM... IDK!
I'm pretty much stuck right now! Owner is picking truck up later this evening......

[Aloicious]

I'm using a 4 pin relay... I'm 99% sure Battery goes to 30 and fan + goes to 87 and since it's negative trigger(PCM pin #42) 85 goes to pin #42..... 86 any 12+ volt source
Maybe it needs to be a 0411 PCM... IDK!
I'm pretty much stuck right now! Owner is picking truck up later this evening......

you are correct on the relay wiring.

I thought you were using a 411. I would think your PCM would be the same, but perhaps that is the issue. Paul or Ross may have to answer that for you.

I still can't check the tune, I'm at work without wireless internet on my tuning laptop, but make sure like the AC pressure settings aren't too low, making it switch on all the time or something.

[GAMEOVER]

It's the stock PCM from the truck, it's a 2000 Silverado with OS 09381344. I replaced the stock fan & clutch....These are the parameters i tried lowering and raising but PCM doesn't respond