LS7 crate engine with E67 ecu. No FAN output

[HRD]

I have a mildly modified crate LS7 in a 67 Camaro with the GM controller kit 19166567 using an E67 ECU. This harness has a single fan relay that takes a ground signal from the ecu to turn it on. I cannot get the ecu to turn on the relay no matter what I do. I have tried manually turning on the fan in the VCM scanner and still no output from the ecu. Everything else seems to be working fine. The relay and wiring are fine. I can get the relay to come on if I touch a test light to the terminal that the ecu should ground to turn it on and the fan works.

Please help. TIA.

[planethax]

Check connection at pcm
use a high impedance test light at pcm and check for ground while commanding Fan on in vcm controls.

If nothing it would seem like a defective pcm.

[planethax]

You have fan type set at discreet, which I believe is correct.
Maybe someone else can chime in for sure.

[Shrek]

Discreet is correct. Someone has changed the number of fans from 2 (GMPP parameter) to 1.

Try returning this value to 2 fans - just a guess - rarely work with GMPP controllers.

[HRD]

Discreet is correct. Someone has changed the number of fans from 2 (GMPP parameter) to 1.

Try returning this value to 2 fans - just a guess - rarely work with GMPP controllers.

Thanks for everyones help so far.

I changed the # of fans to 1. I also tried switching it back to the original parameters of 2 fans, but it made no difference. I looked at the terminal at the relay that turns the relay on and found two wires that go back to the ECM. One wire goes to connector J1 pin 54 and the other goes to J3 pin 49. Not sure why it takes two wires to turn on a relay...

[planethax]

Some use 2 wires to pcm and 3 relays if it has 2 speeds.

not familiar with this specific set-up, what vehicle should I be looking up to see schematic? or do you have the engine wiring schematic?

[HRD]

Some use 2 wires to pcm and 3 relays if it has 2 speeds.

not familiar with this specific set-up, what vehicle should I be looking up to see schematic? or do you have the engine wiring schematic?

Yeah, that's what I'm used to as well. This is a stand alone controller kit from GM that they sell for their crate engines. It uses only a single relay for a single speed fan. I used one of these GMPP controller kits on an LS376 crate engine and it was the same way with only one fan relay, only the fan actually worked right on it. GM controller part # 19258553

[planethax]

Does it not come with a wiring schematic?

[HRD]

I don't have a schematic.

[Shrek]

... One wire goes to connector J1 pin 54 and the other goes to J3 pin 49. Not sure why it takes two wires to turn on a relay ...

J3 pin 49 is the Low Fan output, J1 pin 54 is the High Fan output.

If using a single relay / fan setup - wire J3 pin 49 to ground the low voltage side of the fan relay (to activate the relay high voltage output to the fan).

[planethax]

Ya I have been googleing for a schematic but no luck.
Why they wouldnt supply one with kit is beyond me.

[95wagon]

Thanks for everyones help so far.

I changed the # of fans to 1. I also tried switching it back to the original parameters of 2 fans, but it made no difference. I looked at the terminal at the relay that turns the relay on and found two wires that go back to the ECM. One wire goes to connector J1 pin 54 and the other goes to J3 pin 49. Not sure why it takes two wires to turn on a relay...

As per the 06 CTSV wiring ( with GMPP suggests following)

J1 54 is high fan

J3 49 is low fan

In a simple system, each would ground a different powered relay to operate each fan .
The GMPP harness I started with only had one of those wires , I added the second as my car has two separate fans .
I made no changes in the cal, all my settings are the same as yours but set two 2 fans.
Not sure of the exact temps but both my fans do come on , one after the other.
Hope this helps you

[HRD]

Thanks for the help. I checked to see if I was getting any ground signal output from the ECU to turn on the relay, and nothing on either the high or low fan pins.