V1 Radiator Fan wiring

[jayrolls]

Problem, radiator fan does not turn on.
I have verified that the fan is good. I have verified that I have 12V with key off and on at the relay slots 30 and 85 circuit 9142 at the fuse box. I read the signal wire for the PCM C1 pin 51 to the fuse box slot 86 circuit 335, it has continuity. Fuse box slot 87 circuit 409 has continuity to the fan positive. When the engine is up to fan operating temp nothing happens. I have tried using HPTuners VCM scanner to control the fan to turn on and still nothing. If I pull the relay and jump either slot 30 or 85 to slot 87 the fan will turn on. I have swapped the relay with the aftercool/heat exchanger relay and the fan relay works fine for the heat exchanger fan. So I don’t believe the relay is bad. I’m kinda at a lose.

 

[Gtstorey]

Will HP Tuners Scanner control the fan, or anything else? Or do you mean you have used HP Tuners Editor to change the "tune" to control a turn on temperature? What engine temperature are you checking it at? If you aren't setting the temperature to something lower, then the temperature may be much higher than you think. My Camaro didn't turn on until 227 degrees stock.

If you are sure that it is supposed to be cutting on at the temperature you are checking it at, you should be getting continuity to ground at fuse box slot 409/86 when the fan is "on". If not it is likely something wrong in the ECM.

Depending on the cut on temperature for the "high speed" fan you might be able to use cool/fan 2. If you can set 100% fan within HP Tuners to a low enough temperature, it should work, provided the ECM fault isn't shared between the High and Low Side.

Also, make sure the wire connections are tight in all of the connectors, I chased this for a long time on mine. You may get continuity when everything is apart to check things but not while plugged together.

 

[jayrolls]

Will HP Tuners Scanner control the fan, or anything else? Or do you mean you have used HP Tuners Editor to change the "tune" to control a turn on temperature? What engine temperature are you checking it at? If you aren't setting the temperature to something lower, then the temperature may be much higher than you think. My Camaro didn't turn on until 227 degrees stock.

If you are sure that it is supposed to be cutting on at the temperature you are checking it at, you should be getting continuity to ground at fuse box slot 409/86 when the fan is "on". If not it is likely something wrong in the ECM.

Depending on the cut on temperature for the "high speed" fan you might be able to use cool/fan 2. If you can set 100% fan within HP Tuners to a low enough temperature, it should work, provided the ECM fault isn't shared between the High and Low Side.

Also, make sure the wire connections are tight in all of the connectors, I chased this for a long time on mine. You may get continuity when everything is apart to check things but not while plugged together.

1) not 100% if VCM scanner will work. But it shows to have to functionality. Has a section to turn on/off the fan and control the speed.
2) I’ll have to double check my tune to see what the fan is set at. I want to say it’s 200.
3) I have let it hit 225 and nothing.
4) I can try using a jewelers to ensure that the pins are fully seated in the pcm connector. I feel that the black box plug on the bottom of the fuse box have to be good because I am reading through the top of the fuse box at the relay slots.
The other question would be does the engine need to be running while using VCM scanner? I haven’t tried that, only with key on ignition off.

 

[Gtstorey]

It's very possible that HPT scanners will control the fan. I'm very much new to HPT, but I haven't ever noticed that function or read that it would control things. I thought it was purely a one direction (to the scanner) tool. I know the tech2 scanners will control it.

I would get it up to temperature and check for ground at the pin listed above once you determine that the fan should be on.

 

[Gtstorey]

It looks like yes, HPT scanner will control some of the functions on different vehicles including fans, but it can be problematic at times.

 

[jayrolls]

It looks like yes, HPT scanner will control some of the functions on different vehicles including fans, but it can be problematic at times.

Ok, so wanted to check my tune settings. One is what the base tune was, the other it what my current tune sets at. I should be able to adjust the fan to turn on at a lower temperature and feel safe with the temp range?

 

[Gtstorey]

I would set it to 100% at 200 degrees and zero below that. I'm not sure how the less than 100% works within the the wiring diagrams since it looks like it is either low speed with both fans running at a reduced voltage (in series) or high speed with both fans running full voltage (in parallel). With it set to 100%, I think you should be able to use either cool/fan relay 1 or 2.

 

[jayrolls]

I would set it to 100% at 200 degrees and zero below that. I'm not sure how the less than 100% works within the the wiring diagrams since it looks like it is either low speed with both fans running at a reduced voltage (in series) or high speed with both fans running full voltage (in parallel). With it set to 100%, I think you should be able to use either cool/fan relay 1 or 2.

Alright, a couple of things. Set the the tune to 100% fan at 199.4. Fan turns on as it should. Found also that with VCM Scanner, with the engine running I was able to enable the fan, however I could not get it to turn back off. Shut of the engine and turned back on and fan was off.
Thanks all for the help. Another thing off the list.