ABS melting main relay wire

[fatsooo]

I'm melting the red and yellow wire on my '89 at my main relay. After a bit of investigation thru diagrams, I see its an ABS power wire that leads to the ABS pump and control box.

This is the second engine harness I put in.

First one burnt thru all the way to the connector closest to the firewall near the fusebox in pin 20 I believe it was which lead to a ground under the dash. The car wouldn't start, it would just smoke from that wire. Thought it was just a harness issue so I replaced with a new one and having same issue. (And yes I replaced the burnt thru wire after the connector)

Don't know how to tackle the situation from here considering I didn't touch anything ABS related besides slightly move the pump to clean the engine bay. Nothing enough to alter any of the wiring IMO.

When attempting to start the car again with the new harness, same exact wire got real hot and started smoking so I just disconnected the battery and haven't touched it since.

I'm new to electrical issues so please bare with me and thanks in advance !

[jlevie]

What year car do you have and what year car did the harness come out of?

My suspicion is that the car was built on or before 8/87 and you are using a harness from a car built on or after 9/97. If that is the case pin 20 of C101 on this car is a ground, unlike later production cars. To use the later harness on the car you need to pull back the boot of and cut the wire going to pin 20 on the body side of the connector.

The next problem you'll run into will be that the tach and econometer won't work and the engine may not start, depending on when the harness was built. On the early cars the DME START input, tach and econometer outputs reach the car via a three pin pigtail off engine harness near the DME connector. On late cars those signals are routed through C101. You can add those to C101 or splice the pigtail & connector into the harness.

[fatsooo]

What year car do you have and what year car did the harness come out of?

My suspicion is that the car was built on or before 8/87 and you are using a harness from a car built on or after 9/97. If that is the case pin 20 of C101 on this car is a ground, unlike later production cars. To use the later harness on the car you need to pull back the boot of and cut the wire going to pin 20 on the body side of the connector.

The next problem you'll run into will be that the tach and econometer won't work and the engine may not start, depending on when the harness was built. On the early cars the DME START input, tach and econometer outputs reach the car via a three pin pigtail off engine harness near the DME connector. On late cars those signals are routed through C101. You can add those to C101 or splice the pigtail & connector into the harness.

My car is an 89 and the harness is from a 90

[fatsooo]

My build date is 7/88 and I double checked with the seller of the harness and its from a model year 90.

The other harness that burnt all the way through was off a model year 91.

[jlevie]

Then it sounds to me like there's a problem on the body side, like a short.

[fatsooo]

Then it sounds to me like there's a problem on the body side, like a short.

I compared my old harness (the one that worked fine but i took out for other reasons) to the one in the car right now. One thing i noticed that was different when comparing where the main relay connects, is the one in the car now has that red and yellow abs wire where as the original one does not. the only wire that goes to the connector is the blue and red wire.

[fatsooo]

Bump? Trying to get this issue sorted by the end of the weekend hopefully.