Re: Blowing Backup Light Fuse

[Luis A Marques <marques@ti.com>]

Larry:

Have you checked the wiring in the trunk?  I used to have the same problem on
my 4000q and it turned out to be that 9 years of opening and closing the trunk
had taken its toll on the wire insulation and the wires were all shorted.  What
happens is that the wire for the back-up light is making contact with the ground
wire, but since the car is not in reverse, nothing happens.  But as soon as you
shift into reverse, you get a short circuit and the fuse blows.

Luis
87 4kcsq


LCSCHADT@aol.com wrote:
> 
> I keep blowing the fuse for my backup light, instruments (tach/fuel guage, &)
> on my '87-5ksq.  Some times go a week between events, other times 2-3 times
> in one day.  One and only time I've actually noticed the guages go as I
> watched, it was as I put it into reverse, and another time (before that) I
> replaced the fuse,  started the car, had the guages,  put it into reverse,
> off the parking break,  started to back out of the drive, and had lost them
> by the time I looked back at the guages.  But it doesn't happen every time I
> put it into reverse.  As the "ABS off" light comes on for about a minute
> after the fuse blows (and every time one restarts the car until the fuse is
> replaced) I think I would have noticed had it blown during initial startup
> (when I always check the guages), or if it went while driving - so I'm pretty
> sure it is somewhere in the backup light circuit.  I've looked for obvious
> frayed wires near backup lights, and near the switch at the manual
> transmission and haven't noted any.
> 
> Any experience with this one - how likely is it the switch at the
> transmission, compared to running all of the wires behind the dash and hidden
> in the frame, it seems like a quick and simple thing to try (but how likely
> is it to be the source of the problem, how simple, how expensive?).
>  Suggestions as to other sources for the problem are welcome - there's alot
> on that circuit (fuse #12) involved with instrument guages, warning lights,
> and the self-test circuitry.
> 
> Sorry if this one's been covered before, couldn't find anything in the
> archives through the web site.
> 
> Thanks, Larry at lcschadt@aol.com