PCM upgrade?

[dlb21964]

Hey guys, hoping someone can help me with a few PCM questions. I?m running a LS Swap in a 67 C10. The LS is out of a 2004 Escalade and is a 6.0. Obviously the Escalade had a standard belt driven radiator fan that I?ve since swapped to a dual electric fan setup and Vintage Air AC. I have HP Tuners.

My PCM looks to be the original PCM tied to the vehicle-Blue/Green connectors but no provision for the AC request circuit since the PCM is for trucks/SUVs with regular fans.

The fans in my swap do come on and off at the set temps, but I?d like the PCM to handle the idle manipulation when the AC is on.

From my research, it looks like I need a 04 Vette, 04 GTO, or 05-07 V6 truck PCM since they originally used electric fans.

First off, is that correct? If so, can I simply buy the new PCM and have my original VIN flashed in, and then transfer my revised tune from the old to new PCM? I know I?ll need to buy more credits, but is that the way to do it?

Thanks in advance for any information!

[RDF1]

You can use the pcm you have.
Im looking for the wiring we did on a swap last year to get AC request to the PCM.

[dlb21964]

If that is true that?s fantastic news. Everything I?ve read says I don?t have the right PCM. I appreciate your input and time to help.

[bk2life]

The LS is out of a 2004 Escalade !

you turn it on in the ECM, and add the two wires for the fan relays to it.

I just did this about 3 months ago on a 03 silverado.
owner picked up factory fans and radiator, and wiring. it was almsot plug and play.

[Alvin]

Hey guys, hoping someone can help me with a few PCM questions. I?m running a LS Swap in a 67 C10. The LS is out of a 2004 Escalade and is a 6.0. Obviously the Escalade had a standard belt driven radiator fan that I?ve since swapped to a dual electric fan setup and Vintage Air AC. I have HP Tuners.

My PCM looks to be the original PCM tied to the vehicle-Blue/Green connectors but no provision for the AC request circuit since the PCM is for trucks/SUVs with regular fans.

The fans in my swap do come on and off at the set temps, but I?d like the PCM to handle the idle manipulation when the AC is on.

From my research, it looks like I need a 04 Vette, 04 GTO, or 05-07 V6 truck PCM since they originally used electric fans.

First off, is that correct? If so, can I simply buy the new PCM and have my original VIN flashed in, and then transfer my revised tune from the old to new PCM? I know I?ll need to buy more credits, but is that the way to do it?

Thanks in advance for any information!

The ECM will 100% be able to run those fans.

I sell a hotrod A/C bump circuit that mixes in AC compressor signal with the fan output. So if the fans are off.. ac brings the fans to low.. If the fans are low the AC brings the fans to high.

With that ECM you have the option of running a A/C pressure sensor which wil turn the fans on with high side pressure. Some people also run a trinary switch to turn fans on.

[dlb21964]

The ECM will 100% be able to run those fans.

I sell a hotrod A/C bump circuit that mixes in AC compressor signal with the fan output. So if the fans are off.. ac brings the fans to low.. If the fans are low the AC brings the fans to high.

With that ECM you have the option of running a A/C pressure sensor which wil turn the fans on with high side pressure. Some people also run a trinary switch to turn fans on.

Alvin

I?m using your 3 relay harness to control my fans, but only to turn them off/on by temperature. The hot rod bump circuit I was told by guys there at PCM of NC that would not work for bumping my idle or sending an AC request
I?m using a trinary switch from VA for the sensor and it does work the fans on and off by temp.

I?m trying to use my PCM to bump the idle when the AC comes on, or to turn the fans on when the AC is switched on.

[dlb21964]

you turn it on in the ECM, and add the two wires for the fan relays to it.

I just did this about 3 months ago on a 03 silverado.
owner picked up factory fans and radiator, and wiring. it was almsot plug and play.

The SUV/Truck PCMs supposedly do not carry the 12v signal needed to turn retrofitted fans on or off by AC request or bump the idle because they aren’t outfitted with original electric fans from the factory. Only certain service numbers carry the 12v signal. I’ve searched 50 threads on this, and that’s the general consensus. However, I’m not 100% certain a lot of these guys actually know what PCM they have. I figured I’d ask the quite knowledgeable guys here hoping I can finally sort it out.

[Fast4.7]

The SUV/Truck PCMs supposedly do not carry the 12v signal needed to turn retrofitted fans on or off by AC request or bump the idle because they aren?t outfitted with original electric fans from the factory. Only certain service numbers carry the 12v signal. I?ve searched 50 threads on this, and that?s the general consensus. However, I?m not 100% certain a lot of these guys actually know what PCM they have. I figured I?d ask the quite knowledgeable guys here hoping I can finally sort it out.

PCM needs to have drive by cable IAC drivers to have an analog ac request. Most Chevy Express vans have them from 03-07. There are specific PCM part numbers and Hardware numbers that have them. My 97 L31 based 383 is running analog request on a PCM that came out of a 2004 6.0L Express that I reflashed to a 2005 GMT800 L31 tune. I run an EV clutch fan on mine though as electric fans are garbage for towing in hot weather and the ac does not cool as well as with a clutch fan. Personally I would put an OEM shroud on it and a clutch fan and be done with it. My 97 van has a clutch fan, my 87 G20 6.0L swap had a clutch fan (the L31 350 I have since put in it has one too) and my 99 Tahoe 8.1L has a clutch fan.

[dlb21964]

PCM needs to have drive by cable IAC drivers to have an analog ac request. Most Chevy Express vans have them from 03-07. There are specific PCM part numbers and Hardware numbers that have them. My 97 L31 based 383 is running analog request on a PCM that came out of a 2004 6.0L Express that I reflashed to a 2005 GMT800 L31 tune. I run an EV clutch fan on mine though as electric fans are garbage for towing in hot weather and the ac does not cool as well as with a clutch fan. Personally I would put an OEM shroud on it and a clutch fan and be done with it. My 97 van has a clutch fan, my 87 G20 6.0L swap had a clutch fan (the L31 350 I have since put in it has one too) and my 99 Tahoe 8.1L has a clutch fan.

Yes. This is exactly what I?ve discovered in my research. It doesn?t look like my PCM has the IAC drivers, and my PCM is DBW.

So that leads me back to my other question?.do I order another PCM using the VIN I have now, then simply reflash it with a 04 Vette/GTO tune and then manually move over my individual settings etc or do I need to order the PCM flashed with a VIN number from the above listed 04 Vette/GTO or V6 truck Express Van etc?

[Alvin]

Alvin

I?m using your 3 relay harness to control my fans, but only to turn them off/on by temperature. The hot rod bump circuit I was told by guys there at PCM of NC that would not work for bumping my idle or sending an AC request
I?m using a trinary switch from VA for the sensor and it does work the fans on and off by temp.

I?m trying to use my PCM to bump the idle when the AC comes on, or to turn the fans on when the AC is switched on.

That's not the purpose of the bump circuit. Its meant to mix the fan speeds with temp/AC use. Typically on a hotrod you can run the idle just a touch higher (like 25-50 rpm) with some reserve torque and be ok as the AC cycles on and off.