multmigs

iTrader: (2)

Just spent all day, not really its just friggin cold.. putting in my new 05 fans on my 01 2500HD, everything went together nice (not easy) and after installing my PCM4less.com harness and reprogrammed PCM, I don't have the fans running.. THat said I did test the fans this AM using a car battery both worked and I got the orientation for the +/- for the GM pigtails and then crimped them onto the harness.. At first I thought it was just too cold out, but after 1 hr driiving nothing was strange and the temp gauge was just to the left of 210 where it used to be.. Then I wondered about the AC, as I've read that at least 1 or both? are supposed to be triggered by this on regardless of temp, I checked at my next stop and they're NOT ON!!!! THen I've let it idle in my driveway for 40 mins and I have no fans on and the temp is moving slowly to the right of the 210, I also hear something like bubbling in the overflow bottle which is NOT NORMAL.. So assuming theres no defect in the programming, how do I go about diagnosing this? my first thought is just unplug the fans themselves and put a voltmeter to the plug ends? I'm assuming they will be dead, so then what? I did recheck the ground and + and they are both attached... everything else is like I got it... I have not messed with the manual switched wire which is just taped up to the harness..... THIS IS BS For the close to $750 I have wrapped up in this deal...

XLR8NSS

iTrader: (4)

If all the wiring is hooked up right it sounds like a programming problem to me. I wonder if PCM4less has a copy of the program he made for you. Maybe he could check to make sure the right setting were switched on in the computer. The fan setting must be set to Auxillary for the fans to work. This can only be done with a programmer though. Does anyone around you have a programmer like EFILive or HP Tuner that they could pull an image of your tune outta your computer with and look at?

If the fans worked with a hot source hooked up and the wiring is all right(double checked?) then it has to be in the tune I'd say.

Are there any fuses or fusible links in the harness that are bad?

Eye-P

iTrader: (2)

Sounds like an installation issue to me.

I would make sure that you used the right pin on the PCM connector.

XLR8NSS

iTrader: (4)

Yep, it should be connected to Pin 42 on the connector closes to the engine.

multmigs

iTrader: (2)

I double checked all my hookups, and yes its definately in spot #42 believe i spent like 30 min f'in with gettin it in there so I was staring at the # which is imprinted on there the whole time... I'm gonna check that wire for power? that is what its for right, the pcm tells it to put the fans on so it gives power to the 2 relays which close and push power from the battery to the fans?

XLR8NSS

iTrader: (4)

Pin 42 grounds when the fans are supposed to come on and when it grounds the relay is energized. Pin 42 is the ground for the relay not the power.

multmigs

iTrader: (2)

ok so what do I do to test if its gettin a signal from the pcm? I have a voltmeter, put the positive lead on the battery terminal and then check if that brown wire is grounding it to 12v?

XLR8NSS

iTrader: (4)

I think that would work but, I'm not all that great with electrical stuff and I don't want to tell you something that'll fry your PCM.

TurboBerserker

iTrader: (1)

Make sure the pin is *all the way* into the PCM harness. Push it until it won't go anymore. I had to use a small punch to get it seated.

SnakeOiler

iTrader: (6)

The best thing to do is ground that relay yourself. If the fan comes on, then you know the hookup is correct and one of two things: (1) your terminial is not properly seated in the PCM connector and therefore not making contact, or (2) PCM programming has not been done properly.

For the fan on the a/c circuit: just flip your HVAC control over to defrost - if that fan doesn't doesn't cycle on and off a bunch of times (and it should do it immediately) then you have a hook up problem.