So ive went through an 87 tpi 5.0l harness completely and fixed all connectors and almost all of the wiring issues. There are 2 wires cut right next to each other (im thinking go to some sort of connector). One wire is a brown wire the ends up factory splicing into multiple brown and brwn/wht wires. Im thinking this is a ground. The other wire is a blue wire. After following the blue wire i found that it splices into an additional connector with what looks like a ground connector. What confuses me is that this wire runs back to the ecm pin d11 . As soon as i figure out these two wires im done thanks!!

 

I don't know the link, but some members post austinthirdgen but I can't remember all the address, if it's .org or .com for the wirirng schematics.

 

3rd-gen wiring diagrams courtesy of AustinThirdGen.Org

 

i was looking on there and just cant figure it out. I am not very good at reading these schematics. I wish i was though.

 

Check out this ECM pinout for the 1227165 ECM from tpiparts.net.

It shows that ECM pin D11 is indeed a dark blue wire that goes to the A/C fan pressure switch. Oddly, though, when I look at the schematics provided by austinthirdgen, it shows pin D11 having a gray wire... However, it does correspond in that D11 is connected to the A/C fan pressure switch.

The austinthirdgen schematic says that this A/C switch would have two wires one gray going to ECM pin D11 and one black and/or black/white going to ground.

Actually, I'm getting quite a few different color combinations for the wires on this switch depending where I look. My Haynes manual has it as dark green and black... However, I would say that it is quite likely that this pair of wires is for the A/C fan pressure switch given that one of the wires goes to D11 on the ECM and the other goes to ground, which is characteristic of the A/C fan switch regardless of wire color.

Here's a picture of what the A/C fan pressure switch and it's connector look like (ignore the jumper wire). I'm not 100% sure that's what it would have been on an '87, but that's what it looks like on my '89 Camaro (even though that picture is from some truck forum...). It connects to the A/C hard line that is mounted to the frame rail on the passenger side near the radiator.

You say that the blue wire goes to an additional connector that looks like a ground connector. In my Haynes manual it shows an additional ground connector coming off the same line that goes from the A/C fan pressure switch to the ECM (D11), this ground connection has a note next to it that says: "Grounded w/ Heater Only." The Haynes also shows that in cars with the "Heavy Duty Cooling" option (dual fans?) that instead of this "Heater Only" ground, this wire would have gone to the heavy duty cooling fan switch. However, I don't know if the heavy duty cooling option was available in '87.

Also, all this Haynes manual stuff I am getting is in the manual under "88 and up TPI engine." The schematic they gave for '87 didn't show any additional connections on the D11 wire besides the A/C switch. Basically it would be nice to take a look at a GM Service Manual to be sure... I'm not sure I totally trust the Haynes.

Well, that was a lot of typing... I hope there's some info there that helps.

 

that would be why i couldnt find the blue wire ha. i do believe this harness may have a dual fan setup. I dont know if the previous owner installed it or not. Also the type of connector that is pictured in that link looks simular to a connector i replace on another set of wires. Is this connector used in other places? thanks

PS this forum is awsome. You ask a question you get answers. This is how it is suppost to work thanks again

 

Yes, I believe the A/C High Pressure Switch uses a very similar connector. On my car this high pressure switch was located in the compressor. It's connector was near the compressor clutch connector.