I took on a 12 mile drive and only had it in "D" and no warning light. When I got back home I put it in "R" and the light came on almost immediately. So maybe it is an ECU issue?It is supposed to get 12V on reverse cos that wire is connected to the reverse light circuit so that's ruled out... did you drive it only forward since and you can confirm that the HDC warning doesnt come on that way too ? at this point i can't find any logical explanation why this happens only on reverse and if the wire is unpinned it doesnt happen unless it's an ECU misbehaviour
sierrafery
Well-Known Member
I can't find any logical explanation for that, it's first time i see such oddity... to rule out the ECU would be a good move though it can be a short somewhere between that reverse light input and other, the circuits to reverse input and HDC relay are going through the same header C0287(pins 1 to 6/reverse and 16 to 20/HDC relay which are in parallel), i've neves seen water ingress in that area cos that header is wrapped into the harness though corrosion there can cause such thing
Thanks again for your continued help. I guess I will take a look at header C0287. As my truck is LHD , it looks like this header will be blue, have 20 pins and be located under the glove box near the blower fan. Does that seem right? If I don't see anything wrong with C0287 should the ECU be replaced? If so since it is 2004 do I need PN SRD500070? If I just disconnect the wire again what will be disabled? I had been driving it that way for 4 years before finding it.
sierrafery
Well-Known Member
If it's an ECU fault i dont know how it will behave with that wire disconnected, normally it should affect only the HDC in reverse. If you decide to replace the ECU yes, SRD500070 is needed but if everything works with the wire disconnected maybe it's better to just let it be
Since everything was working, I think I will just disconnect it again.
