another wiring question! HELP!!!

[v8power]

at a junk yard here there is a Pontiac grand prix with a v8. I want the wiring harness for my regal that came with a 3.8. my question is, should i take the whole harness or will the plug ins on the fire wall hook right up? i am not worried about the gauges at all. sorry to keep asking all these wiring questions , but i do not want to buy something and not have it work, besides that, I HATE WIRING.

 

[85 Cutlass Brougham]

That is how I did my swap. I used the harness from an 85 SBC 305 powered Grand Prix to work with my 85 Cutlass V6 car and had no glitches other than some of the gauge wiring. You may wish to be sure the two cars are the same model year as there is a possibility that GM changed the pin-outs from year to year. You only need the engine harness and not the headlight harness. They separate when you unplug it from the bulkhead connector under the wiper motor. You will need to unbolt the connector using a 1/4 in socket. Be sure that the donor vehicle has A/C if you have it and wish to retain it as it is on this harness. This harness does not include the cruise control or any of the engine management ( computer) circuits. It does have the ignition, starter motor, A/C, alternator and gauges on it.

 

[v8power]

i also found a few non a/c heater boxes i am going to pull off, they only wanted 15$ for them.

 

[v8power]

i was just wondering what wires are on the passenger side of the car? are they just emissions, ac/ and gauges. so would that mean all i need is the drivers side harness where it plugs into the fire wall? also this car is not a hei distributor, so can i get a adapter to run one or not?

 

[85 Cutlass Brougham]

The wiring on the passenger's side is a mixture of two separate harnesses. The computer harness comes out of the firewall on the passenger's side underneath the HVAC box. The computer harness and the main ignition/charging/A/C harness is one of the two harnesses that plug into the main bulkhead connector under the wiper motor. It plugs into the harness that the blower motor and it's ancillaries plug in to. That is a 4 wire plug and it is universal to all engines except maybe turbo or diesel applications, so you can just reuse your original there. So, the harnesses in the engine bay are as follows: Computer, main engine, Cruise Control ( comes out of a grommeted hole right of the steering column that is only drilled in cars so equipped), lighting and minor A/C harness. You only need the main harness for a swap that does not include the computer. When pulling your harness however, be sure it is complete and factory with no spliced in wires or crimp connectors that GM did not supply. Also, if possible, try to get one with the steel tube that acts as a heat shield for the starter wires still intact. This protects them from the exhaust system.

 

[v8power]

you are the man.. thanks allot. just one more question, is there a plug in on the passenger side, or dose that just run to the gauges, tail lights ect?. so what i am getting here so far is that all the main components run off the plug in below the wind shield motor right?

 

[85 Cutlass Brougham]

The tail lights are run off of 2 subharnesses. One is plugged into the side of the fuse box and has "metallic" looking wires which are single strand and not multi-strand copper like the rest of the harness. They go back to the main tail light harness at a plug in the rear corner of the trunk on the driver's side. These are not a concern as you should not have to do anything with them unless you take out the dash. (The fuse box and bulkhead connector are part of the dash harness) The gauges are also run off the main harness that runs the ignition, etc and plugs in to the bulkhead connector under the wiper motor. The harness on the passenger's side does not have a plug, but rather a grommet and a 2 bolt clamp that keeps it in place. This is the computer harness and the hole will need to be covered by a block off plate. I made mine from a piece of sheet metal that I caulked in place with seam sealer and screwed to the hole with the original screws and the bracket on top, so that I do not loose it if I ever need to put it back to stock. You could also use butyl acetate strip caulk to do this. In fact, be sure the bulkhead connector seals to the car after doing this swap. If not, strip caulk ( available from your local auto body jobber or Eastwood) can be used to seal the hole very easily. It forms to the shape you make it by pushing it in with your fingers. It is important to be sure the firewall is sealed or else water will go under the carpet and rot out the floors.

 

[v8power]

wow that is alot of wires that i do not need!!

 

[dougfather]

I'm goping through the same situation. I am planning on using AutoMeter gauges instaed of idiot lights. I also plan to do a "haircut" on my V6 harness. I won't be using the ECM, so a lot goes away.

 

[85 Cutlass Brougham]

I think the V6 harness may be OK so long as the starter is on the passenger's side and not the driver's side like it is on the Olds V8's. If not, I would get the right harness as you do not want to splice extra wire into a high current draw circuit like the starter. Remember that on a GM car the starter's battery positive post is also the main serial bus for the entire electrical system A spliced connection will add resistance to the line and will eventually deteriorate if done improperly. Plus, you want to keep the factory fusible links intact as a safeguard against electrical fires caused by faulty wiring and shorts. If you are running the A/C, the compressor will be on the opposite side on a Chevy if it is a V belt car, and the Alternator is also on the opposite side. Both of these circuits are probably too long, but I would not cut and splice the alternator circuit because of it's fusible links. Remember that the alternator needs to have 2 fusible links in it's wire that charges the alternator. This is because you need to guard against power flowing from both directions and not just one. So, you need the link at the battery end and at the alternator end because you do not know if or where a short will develop on that wire and only breaking one connection does not make the wire stop being hot.