Wiring Harness Lq4 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Vandals909 · 11-10-2015, 05:55 PM

I'm curious how a stand alone harness is wired to work with the A/C from the 2006 lq4 I have.. Does it just control turning on the accessory electric fan when the A/C kicks on? What does the harness really control in regards to the a/c

I ask because I priced out a harness through current Performance and it includes wiring for the engine, a/c and 2 electric fan relay.

http://www.currentperformance.com/sh...tc-bare-bones/

However, there is a company which is about 20 minutes from my house that also does harnesses. They install engines in everything from $100k plus sandrails, to hot rods.

http://store.custombuiltmotors.com/e...n-oem-ecm.html

They are more expensive then current. But they are local in case I run into any issues. The only issue is they are telling me the harness has nothing to do with the a/c?

Trying to decide with harness to go with, thinking the local company

rmvlt1100 · 11-11-2015, 12:19 AM

I purchased mine from PSI Conversions. They were great to work with and answered any questions that I had. When I called them to place my order they made one to fit my application. Below is a link for them.

http://secure.ultracart.com/catalog/...X/4L60E-4L80E/

Good luck with your build.

Quote:

Originally Posted by Vandals909

I'm curious how a stand alone harness is wired to work with the A/C from the 2006 lq4 I have.. Does it just control turning on the accessory electric fan when the A/C kicks on? What does the harness really control in regards to the a/c

I ask because I priced out a harness through current Performance and it includes wiring for the engine, a/c and 2 electric fan relay.

http://www.currentperformance.com/sh...tc-bare-bones/

However, there is a company which is about 20 minutes from my house that also does harnesses. They install engines in everything from $100k plus sandrails, to hot rods.

http://store.custombuiltmotors.com/e...n-oem-ecm.html

They are more expensive then current. But they are local in case I run into any issues. The only issue is they are telling me the harness has nothing to do with the a/c?

Trying to decide with harness to go with, thinking the local company

aknovaman · 11-11-2015, 12:26 AM

Seriously, $750 for a harness without a PCM and no tune, No check engine light or fan relays.

I know I am cheap but some retailers are way overpriced for my taste.

If it's a driver, you can rework a Factory harness, junk yard PCM and get a mail order tune for way less. With the left over $$ you can buy a mild-medium cam and springs.

MalibuSSwagon · 11-11-2015, 12:48 PM

AC is usually wired thru the PCM, when AC request is sent the PCM kicks up the idle, and turns on the secondary fan. You don't have to do it this way, you can just use your original or aftermarket (think Vintage Air) wiring. You just won't get the slight idle bump.

foamypirate · 11-11-2015, 01:03 PM

Quote:

Originally Posted by MalibuSSwagon

AC is usually wired thru the PCM, when AC request is sent the PCM kicks up the idle, and turns on the secondary fan. You don't have to do it this way, you can just use your original or aftermarket (think Vintage Air) wiring. You just won't get the slight idle bump.

The main problem I've run into is that the 03+ truck PCMs require a serial request for AC instead of a 12v+ request. Looks like HPTuners now has the capability to switch, but the harness has to be built correctly to function with it. You'll want to make sure the harness builder can setup the PCM and wiring harness correctly to function with a 12v+ request from the factory AC head/wiring, at least if you want PCM controlled fans with the AC on.

I also looked at using a pressure switch to control the ground side of the fan relays outside of the PCM control, so when AC pressure are high enough they'll kick on. With highway airflow, the pressure should drop enough that the fans shut off. This seems like the 2nd best approach for AC fan control, at least to me.

aknovaman · 11-11-2015, 02:22 PM

Have you read this about green blue pcm and ac?

http://ls1tech.com/forums/conversion...ector-ecu.html

72LSK10 · 11-16-2015, 11:05 PM

Bill at BP Automotive will set you up the right way with your tuning and harness, he's good and his work is extremely nice. I had so many questions and he took the time to explain everything to me and why it is important to have to correct set up when running AC. Give him a call, you won't be disappointed.

http://shop.bp-automotive.com/

http://www.bp-automotive.com/LS1_Sta...Harnesses.html

11-10-2015, 05:55 PM	#1
Vandals909 Registered User Join Date: Sep 2005 Location: So. Cal Posts: 321	Wiring Harness Lq4 I'm curious how a stand alone harness is wired to work with the A/C from the 2006 lq4 I have.. Does it just control turning on the accessory electric fan when the A/C kicks on? What does the harness really control in regards to the a/c I ask because I priced out a harness through current Performance and it includes wiring for the engine, a/c and 2 electric fan relay. http://www.currentperformance.com/sh...tc-bare-bones/ However, there is a company which is about 20 minutes from my house that also does harnesses. They install engines in everything from $100k plus sandrails, to hot rods. http://store.custombuiltmotors.com/e...n-oem-ecm.html They are more expensive then current. But they are local in case I run into any issues. The only issue is they are telling me the harness has nothing to do with the a/c? Trying to decide with harness to go with, thinking the local company

11-11-2015, 12:26 AM	#3
aknovaman Registered User Join Date: Aug 2013 Location: Tecumseh Posts: 355	Re: Wiring Harness Lq4 Seriously, $750 for a harness without a PCM and no tune, No check engine light or fan relays. I know I am cheap but some retailers are way overpriced for my taste. If it's a driver, you can rework a Factory harness, junk yard PCM and get a mail order tune for way less. With the left over $$ you can buy a mild-medium cam and springs. __________________ Current project 1959 Willys = GEZR TRUK Geezer is a Latin compound word made up of two roots. Gee meaning Urine Stain and Zer meaning your pants are open! FMCDH GBU and GBA http://www.youtube.com/user/aknovaman/videos Last edited by aknovaman; 11-11-2015 at 12:32 AM.

11-11-2015, 12:48 PM	#4
MalibuSSwagon Registered User Join Date: Sep 2009 Location: Weare,NH Posts: 1,592	Re: Wiring Harness Lq4 AC is usually wired thru the PCM, when AC request is sent the PCM kicks up the idle, and turns on the secondary fan. You don't have to do it this way, you can just use your original or aftermarket (think Vintage Air) wiring. You just won't get the slight idle bump. __________________ Eric 1992 Oldsmobile Custom Cruiser 1986 Chevrolet C10\|5.3L\|TKO600\|Shortbed\|Custom Deluxe 1983 Malibu Wagon\|TPI 305\|T5 5 speed\|3.73 non-posi

11-11-2015, 02:22 PM	#6
aknovaman Registered User Join Date: Aug 2013 Location: Tecumseh Posts: 355	Re: Wiring Harness Lq4 Have you read this about green blue pcm and ac? http://ls1tech.com/forums/conversion...ector-ecu.html __________________ Current project 1959 Willys = GEZR TRUK Geezer is a Latin compound word made up of two roots. Gee meaning Urine Stain and Zer meaning your pants are open! FMCDH GBU and GBA http://www.youtube.com/user/aknovaman/videos

11-16-2015, 11:05 PM	#7
72LSK10 Registered User Join Date: Oct 2011 Location: Long Beach, CA Posts: 127	Re: Wiring Harness Lq4 Bill at BP Automotive will set you up the right way with your tuning and harness, he's good and his work is extremely nice. I had so many questions and he took the time to explain everything to me and why it is important to have to correct set up when running AC. Give him a call, you won't be disappointed. http://shop.bp-automotive.com/ http://www.bp-automotive.com/LS1_Sta...Harnesses.html



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