Minor Problem - Need Help with Backup Light Circuit Issue
Thread Starter
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Minor Problem - Need Help with Backup Light Circuit Issue
I noticed tonight that my backup lights were not working when I'm in reverse, but do when I use my keyless entry (i.e. approach lights). I went under the car and did some troubleshooting on the Backup Lamp Switch on the tranny (MN6). After checking everything out, I traced the immediate problem to the mini-fuse in the passenger footwell fuse box - it feeds the circuit when the ignition is ON and it was blown. I replaced the fuse and immediately blew again when I put the car in reverse.
I have a suspicion that the backup lamp switch on the tranny is bad, but don't see how it could cause a short since the tranny isn't grounded (aluminum). Has anyone had a similar problem? Does the Backup Lamp Switch have some impedance or is it just a contact switch?
:confused:
I'll do some more troubleshooting on the weekend and then likely need to bring it in for a fix, but any help in isolating this is appreciated.
John
I have a suspicion that the backup lamp switch on the tranny is bad, but don't see how it could cause a short since the tranny isn't grounded (aluminum). Has anyone had a similar problem? Does the Backup Lamp Switch have some impedance or is it just a contact switch?
:confused:
I'll do some more troubleshooting on the weekend and then likely need to bring it in for a fix, but any help in isolating this is appreciated.
John
Thread Starter
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Re: Minor Problem - Need Help with Backup Light Circuit Issue (JC in XTC5)
Just did a search an noticed that a failing backup light switch is a common problem. I don't see anyone else getting a blown fuse though, but I have a few ideas to isolate the problem to the switch now.
Melting Slicks
Joined: Mar 2001
Posts: 2,670
Likes: 850
From: New Jersey
Re: Minor Problem - Need Help with Backup Light Circuit Issue (JC in XTC5)
Aluminum conducts, and the tranny case is grounded thru the torque tube, to the engine block. Maybe the switch internals have connected to the switch metal base, which is screwed into the grounded trqanny case. Are there one or two wires to this switch?? (Probably two is my guess, which supports my failure theory)
Drifting
Joined: May 1999
Posts: 1,976
Likes: 0
From: Herndon Va
Re: Minor Problem - Need Help with Backup Light Circuit Issue (ersatz928)
The switch on the MN6's for the backup lights is a common problem - had mine fixed a couple of months ago. Maybe part of the fix is a new fuse but I can't tell from the work order.
Thread Starter
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Re: Minor Problem - Need Help with Backup Light Circuit Issue (ersatz928)
Aluminum conducts, and the tranny case is grounded thru the torque tube, to the engine block. Maybe the switch internals have connected to the switch metal base, which is screwed into the grounded trqanny case. Are there one or two wires to this switch?? (Probably two is my guess, which supports my failure theory)
Thanks
