First: No, you do not have to run any wires at all. Clip the harness off of your stock '86 harness. The splice directly into the late harness, all inside the glovebox.
This example is a "late production early" '86 325, 10/85 DOM. In other words, the car has a round C101, but still an ETA.
The harness is an '89 325i harness with a 173 DME.
The 2 wires that need to be added to the stock DME harness are located in a white 3 pin plug: ours had white, shielded green and black wires.
The other side of the plug had Yellow/White, but switched to white after the plug (on the stock '86 DME harness) shielded green (which switched to black) and a small green.
The small green wire is unused. Apparently it is the stock DME power, I will research it more later.
Green (strip away the shield, it is not needed here) feeds the tach signal to the stock '86 harness. That goes "shielded green--->black". Simply cut the black wire of the '89 DME and splice in the green wire, but make certain to do a flawless job taking the shield off of the green. One spare strand might cause damage, just don't screw up.
The econometer gets a signal from the DME too, that is the "yellow/white--->white---->white/black" (on the '89 harness) connection shown:
BE CAREFUL, there is also a black/white, do not screw that up either.
You can see in the C101 (peel back the boots if you want) that the black wire from the DME does NOT have a corresponding pin on the "car" side, so this is a quick and easy way to actually fix the tach and the econometer, both in about 3 minutes.
The A/C does work properly with this mod as well.
This being inside the glovebox, it is just fine with crimp connections. I re-wrapped the harness and all fit back under the stock covers.
Luke
This example is a "late production early" '86 325, 10/85 DOM. In other words, the car has a round C101, but still an ETA.
The harness is an '89 325i harness with a 173 DME.
The 2 wires that need to be added to the stock DME harness are located in a white 3 pin plug: ours had white, shielded green and black wires.
The other side of the plug had Yellow/White, but switched to white after the plug (on the stock '86 DME harness) shielded green (which switched to black) and a small green.
The small green wire is unused. Apparently it is the stock DME power, I will research it more later.
Green (strip away the shield, it is not needed here) feeds the tach signal to the stock '86 harness. That goes "shielded green--->black". Simply cut the black wire of the '89 DME and splice in the green wire, but make certain to do a flawless job taking the shield off of the green. One spare strand might cause damage, just don't screw up.
The econometer gets a signal from the DME too, that is the "yellow/white--->white---->white/black" (on the '89 harness) connection shown:
BE CAREFUL, there is also a black/white, do not screw that up either.
You can see in the C101 (peel back the boots if you want) that the black wire from the DME does NOT have a corresponding pin on the "car" side, so this is a quick and easy way to actually fix the tach and the econometer, both in about 3 minutes.
The A/C does work properly with this mod as well.
This being inside the glovebox, it is just fine with crimp connections. I re-wrapped the harness and all fit back under the stock covers.
Luke
Comment