I need to start retrofitting my wiring harness to a "stand alone" unit. It's from a 05 express van 5.3. Does anyone have a diagram that shows pcm connector pin outs? Or does anyone have a GM wiring manual for a 05 express van for sale?

 

The pins are the same as the C/K trucks except some of the wires are different colors. Also the van will have TPS and IAC where the 03-06s truck will not show those in the pinouts. To find them you need to go back to the 99-02 pinouts.

Check out lt1swap.com

 

give this a try, pm if you need file emailed

 

That's the wrong schematic. It's for an LY6 with an E38 ECM for model year 2007 and up.

He has the old style Blue/Green PCM in the 05 Express van. Most likely an LM7.

 

oops, sorry. Don't have anything for the older style. Lots of very helpful people here, Im sure someone will be able to help. Good Luck with the build.

 

^ true I have the older style pcm. If I decide to have it done by someone else who would you guys recommend? I looked at speartech and WOW their proud of their work! I mean the harness' look great but for that kind of $ I think I would just hack it up myself!

 

99-02 truck pin-outs or 99-02 f body pin-outs

 

Yeah.. they do some nice work..

You might work with the other sponsor on this forum.. BP Automotive and PSI... They most likely will ping in..

 

03-05 truck pinouts for everything except the IAC and TPS

Use the 99-02 truck to see the IAC and TPS pins.

Ken

 

The van harnesses are kind of lengthy...like literally 12 feet long. PM me your email and I can send you a spreadsheet listing the wires you need to retain for a standalone config.

 

Chk your email.

 

Thanks a lot novaman! Im going to try doing it myself, I have the know how just not sure if I have the patience!

 

Start by removing all the outer black corrugated covering and tape starting at the PCM connectors. At each tree branch, use a zip tie to retain the shape of the harness. Otherwise you will have a huge birds nest of tangled wires. Cut off the main fuse panel connector and zip tie all those wires into one bundle. This will leave you with a naked harness. The remove the blue PCM connector pin cover, it is held on with small tabs on each end. Press them toward the center of the connector with a pocket screwdriver and they will come off. Look at the pins listed on my spreadsheet and retain those. Look at the wire numbers cast into the PCM connector near where the wires enter it. The un-needed wires can be removed either by cutting the wire and pushing the pins through the connector to by lifting the piano key tabs away from the wire and gently pulling the wires back toward the harness. Remove un-needed wires in the same way from the other connector. Then back pull all the un-needed wires from the harness one at a time. The zip ties can then be tightened as the wires are removed. It will shrink in size by about 1/3 of the original size.

Then bundle and label each cylinder bank injector wires like "Bank 1 INJ". Label the coil, MAF, Trans and 02 sensor power wires. They are all PINK. Repeat the bundling for the other cylinder bank. Add fuses to each circuit as you see fit. Orange wires are connected directly to +12v battery to retain PCM memory and power the OBD2 port. Lay the harness on your engine and re-route the crank position wires over the top of the intake and shorten them. Re-route and shorten the O2 sensor 4 wires too. Solder and heat shrink all connections.

That’s enough to get you started.

 

I'm also in search of the wire harness diagram pin-out for my 2007 LQ4 out of a 3500 Express Van. I have the older style PCM too and it's drive by wire.

 

Did you guys check here?

http://www.lt1swap.com/wiringharness.htm

 

As was stated above LT1SWAP.COM has everything you need for that pcm, wire harness, etc...

 

Digging up an old thread but any help would be appreciated. I'm starting my swap using a LM7 from an 04 Express van with DBC. I've got LT1swap information in front of me and looking at my pinouts. At least the green side doesnt match up with the 99-02 or 03-07. I've got different color wires and wires not in the pinouts listed. Not sure where to go unless somebody has some resources. Thanks.

 

What wires are different? The wires you need to keep in your 04 van harness should be real similar to the 99-02 pin outs. Check any of them that are different colors against the 03-06 pin outs to see if the wires go to the same things but just the colors are a little different.

 

Just as one example it has #30 C1(blue connector) on both 99-02 and 03-07 diagrams to be " Light green - Coolant level switch signal". On my harness, there is no pinout at all in that spot. I just want to make sure that I am cutting the right wires.

 

That wire is something you wouldn't need anyway. Check it against the wires that you dont need to do anything to, those should all be the same.