A few remaining wiring tasks for my swap involved wiring up the BCM (body control module) and modifying the A/C circuit. Let's discuss the BCM first. The only circuit on the BCM that I was interested in was the interior light control. In this case, it softly dims the interior lighting after closing the doors, like many new cars do. It also puts the interior lights on a timer. This is a nice feature. For example, when cleaning the car and leaving the doors open, the BCM turns off the interior lights after a preset amount of time. I chose to wire in this feature only. The BCM I'm using is part number: 22682857. This is just a plain BCM and it didn't come with the key-less entry feature.
Since there were many places that I'd have to tap into, I chose to remove the dash. This BCM requires several points of power and these came from a few different circuits. Some require full time power while others need key-on or accessory power. The back side of the fuse panel was chosen for all my power taps. In this manner, all BCM circuits are protected by fuses.
After the primary battery, accessory power and ground was wired to the BCM, it was then time to redirect the power and return for the courtesy and dome lighting to the BCM.
Note: S (ex, S210) stands for a splice location in the harness and C (C200) stands for connector.
I needed to cut the courtesy and reading light supply (orange wire) to make this work.
1) Follow the driver's side courtesy light (orange wire) to the S210 splice location in the harness and cut it leaving an inch or so before the connector. I chose to cut the wire on the “main harness” side.
2) Follow the orange wire coming from the dome/reading lights back to the C200 connector under the dash at the extreme left, upper forward corner. Cut this wire a few inches before it goes into the connector.
Join the orange wire “going to the dome lights”, at the S210, together with the orange wire “going to the courtesy lights”. Attach another wire and run this to the blue connector, pin A10 (Inadvertent Power Control) on the BCM.
This now leaves two orange wires that were previously cut. Extend the orange wire, coming from the C200, (that used to feed the dome/reading lights), to the orange wire that previously fed the courtesy lights (S210 splice location). Join these two wires together and add another length of wire. This goes to the BCM blue connector, pin A12. In reality, the Fiero courtesy light fuse is now feeding pin A12 at the BCM.
Another circuit that needs to be modified to make this all work.
At connector C209, there are two white wires. One goes to the passenger side and this is the one you want to cut. This white wire goes to the Fiero dimmer switch. Cut it around an inch from the connector. Extend this white wire and attach to the BCM brown connector, pin A1 (Courtesy Lamp Control). The other end is no longer used and should be capped.
Having now wired the the interior light's feed from the BCM, I must complete the circuit and add the return path.
Here is the S304 factory splice in the harness. It has four white wires acting as a node. (A place where two or more wires are attached.)
We need to separate these as follows.
Cut the single white wire, from the node, that goes to the right.
This wire leads to the right door jamb switch.
Solder a light blue wire to this white wire (that goes to the right door pin switch) and attach to BCM purple connector, pin A8.
Of the three remaining white wires, one goes to the left door jamb switch.
Follow/trace the correct white wire and cut it at the node.
Solder a light green/black wire to this white wire (that goes to the left door pin) and attach to BCM purple connector, pin A7.
You now have two white wires from the node. These are the courtesy and dome lamp returns.
Solder both of these together and add a length of white wire to this node.
Attach this to the BCM brown connector, pin A1. (Courtesy Light Control.)
At this point, the BCM now turns on and controls the courtesy and dome lights.
To deal with the A/C, I had to modify the Fiero circuit slightly. Since I'm adapting a newer technology Delphi CVC-6 compressor to an older car, I need to make sure they play together nicely. This was easily accomplished.
First, the stock Fiero pressure cycling switch isn't required.
For testing reasons, I removed this connector from the accumulator and jumped the two wires together. Knowing that I've modified the circuit correctly, I will permanently join these two wires together.
I'm doing this because the Ecotec PCM will now control the compressor cycling operations. I will also add in the three-wire pressure sensor to the high side line near the compressor. This must be done for safety reasons. The PCM uses this sensor reading to determine how to control idle speeds, radiator fan operation and A/C compressor clutch operation when the A/C system is turned on.
Note: the PCM will not enable the A/C clutch without having this sensor in place. From a safety stand point, this circuit also protects the A/C compressor. When you get into power enrichment, the PCM de-energizes the relay which turns off the compressor. Thus, saving it from over-speeding.
I then made a little bracket to hold the antenna parallel to the ground. Seeing as I shaved the antenna hole in the fender, this was my solution. I'm sure it's not the greatest position for an antenna to be in, but I use the auxiliary input more than I listen to the radio.
While I was in that general area, I also added new metal to support the passenger's side lower fender. One hole and a little primer/paint, it'll be good again.
Then it was time to get greasy. New CV joint grease was applied to all four joints followed by new clamps. Prior to installing the axles into the car, I installed new axle seals into the F23.
Napa part number: 13750.
I reclaimed this factory GM security unit from the Cavalier that I had here, GM part number: 10953186 .
It's a simple device that requires a fob to be swiped in order for the starter to engage. This will work well for my application and is all I need/want.
Lastly, I picked up a used 130 amp DC TIG welder. It's a portable Thermal Dynamics unit that only welds steel. I tried it and it works well but I will give it a good cleaning before it goes into service.