engine wiring harness

[assang]

Hi, according to my long time mechanic buddy, I have to replace the engine wiring harness. The thermostat was defective earlier and it burnt some wiring. He's thinking I need to replace the engine wiring harness to fix the problem that I'm having. The car is in failsafe mode and can't idle. It can start. It's a 99 540it.

I've replaced the thermostat, MAF, CPS, ICV, fan clutch, etc. According to him, the whole set of engine wiring harness costs about $750 and it takes a week to get here. most dealerships don't stock them.

Have you guys replaced your engine wiring harness before? How expensive is it? I checked realoem and it's about $850.

[xatlas0]

A loom is a very specific thing, although with your car, you should be able to use (just to be safe) any 99+ 540i harness. If you have a local pick-n-pull, see if they have an E39 540, so you can yank it from there for 300 or less.

[assang]

I thought about that too. But I'm afraid I will need to replace them again soon if the wiring harness is old...thanks for the suggestion.

[xatlas0]

I thought about that too. But I'm afraid I will need to replace them again soon if the wiring harness is old...thanks for the suggestion.

Considering it was a malfunction which caused your harness to fail before, as long as you prevent that same type of failure again, the harness (old or new) should last a very long time. I still have the stock harness on my 94 540, and before I switched to Motronic, the original harness on my 72 CS.

[assang]

Thanks. I found a guy with a used set of harness. Let's see how it goes.

[Goat128]

I'll take a wild guess and say a wiring harness lasts 300k miles. I haven't heard those being replaced often at all.