Can someone help sort my hatch release wiring?
02-15-2018, 11:31 AM
#1
Can someone help sort my hatch release wiring? I am presently swapping a4 to m6. I have a 98. I’m trying to sort out the hatch release. When I look at my button, both wires going into it show continuity to ground. Is that normal or do I have a short? My radio bugs out and so does my oil gauge. But I figured the sender was bad and someone told me my radio is showing normal signs of crappin out. I’m lost
02-15-2018, 01:17 PM
#2
The hatch release switch doesn't actually control the release directly. It provides a ground signal to the BCM which then sends power to the coil side of the hatch release relay, tripping the relay and activating the release solenoid. On an automatic, the ground for the coil side of the relay goes to the neutral safety switch so that it can only release in park or neutral. With your M6 now, that ground should go to the parking brake switch so that the hatch will only release when the parking brake is engaged (so that you don't release it while driving).
02-16-2018, 07:36 PM
#3
Thanks for the help. I couldnt figure out where the pnp met with the hatch release circuit. Cause I know it runs from the PRDNL harness to the engine harness blue connector under the passenger side kick panel. And then to the pcm. So I was looking at my hatch wires. What I had done was hooked my test light up to a 9v battery and used it as a poor mans continuity checker. I noticed that both hatch release switch wires have continuity to a ground and therefore each other. That’s shouldn’t be the case no? A side note, is when I was checking these with the 9v test light rig, my oil pressure gauge was twitching. My oil gauge was twitching before I pulled the motor for this swap. I just thought the sender was bad. Also my radio volume **** causes the volume to jump low to high to low to high, and the display won’t read right, was blaming that on a bad unit. Now I’m wondering if I have a short. If these two wires only connect with the switch depressed, why are they lighting up my test light when I touch them both to ground
02-17-2018, 07:15 AM
#5
It is not uncommon for a wire to show ground potential when not in use when it's actually connected to some device (in this case the BCM). That doesn't mean that there is a short necessarily. You should get yourself a real test light or multimeter - either one is only about $5 at places like Harbor Freight. Check the brown wire in position D4 of the blue 32-pin connector of the BCM. It is between a black/white wire and a pink wire. It should show 12V power for a moment when the hatch release button is pressed. If not, take a piece of wire and short the black/white wire next to it in position D3 to ground - that is simulating the function of the release button. If shorting that wire to ground makes the hatch release work then you have a faulty button or the wiring between the button and the BCM is broken.
Your radio problems are completely unrelated. The volume problem is not uncommon and can often be fixed by using electronic contact cleaner on the volume control. The display problem is often a bad connection between the face plate and the radio.
Your radio problems are completely unrelated. The volume problem is not uncommon and can often be fixed by using electronic contact cleaner on the volume control. The display problem is often a bad connection between the face plate and the radio.