Rear Wiper and Mirror Fuse issues

[Bozer1991]

1992 SE V6 - My 10A fuse blows 3 seconds after the car turns on. The rear wiper works, goes through one cycle, then fuse pops.  Wiring from truck to door looks good. Any ideas on where to start my search are appreciated!

 

[Slartibartfast]

I'm a little confused on which fuse you're popping. One pops after three seconds, the other pops when the wiper returns? Or is it the same fuse? Looks like the rear wiper fuse should be second from the left, top row.

 

EL-69 of the '90 manual shows the rear wiper wiring. ('95 had the switch on the stalk, so the '95 diagram is different.)

 

You've already checked the first thing I'd check. At this point I'd pull the driver's side cargo area trim panel and see if there's anything obviously wrong with the wiring, the wiper amp, or the relay, and pull the trim on the hatch and check the wiring for the motor and its switches. Could be the hatch switch for the dome light was acting up as they do and someone cut the wrong wire, or maybe someone got really lost while installing a trailer harness. If nothing jumps out, I'd unplug the motor and see if it still pops the fuse.

[Bozer1991]

Sorry - same fuse. It's the 10a, 2 spots from the left. It's labeled as both RR wiper and mirrors.

 

Il pulled the rear hatch molding and all wiring looks OK. I will try drivers side cargo area trim now, thx for that tip.

 

The previous owner definitely messed with the trailer hitch area, so I'll inspect there as well.

 

Thx

[Bozer1991]

OK, I unplugged the rear wiper motor and now the power rearview mirrors work, so that's the problem.  I will decide if I am going to hunt down a new motor at the local junkyard.

 

Next problem - the rear/trunk hatch window popper does work, doesn't seem to have power.  Is that on another fuse?  I don't see one in the fuse box.  Wiring all looks OK.  Any ideas on that?

 

Thanks

[Slartibartfast]

Oddly the rear window hatch popper isn't on a fuse, it's on a circuit breaker. It shares that breaker with the ignition relay, so if that was out, you'd have bigger issues.

 

The wiper motor has to be present (and in the correct position) for the hatch popper to work. There's a switch in the wiper motor that prevents you from opening the window when the wiper is in the way. It seems to only hit that switch every other swipe for some reason, so just because the wiper is down doesn't mean it's "home." I've run into this a few times on mine (the wiper's down but the glass won't pop), and I've learned to turn off the wiper, let if find "home," and then turn off the ignition. Of course that doesn't help you now.

 

The wiring diagram for the hatch popper is in the BF section, for some reason. Looks like you could just jumper from green/white to black at the wiper motor plug to bypass the wiper position switch.

[Bozer1991]

Interesting that the wiper arm needs to be all the way down/home and seated in the bracket before that switch will work.  My wiper is definitely not down.  I tried jumping the green/white and black wires at the wiper motor plug, but still a no go on the popper.

[Slartibartfast]

Is the wiper switch on? That also locks out the popper.

 

If there's nothing obvious, check at the actuator, see if it's missing power, or if it's missing ground, to see which side of the circuit needs chasing. If it's missing power, verify +12v on the light green wire at the switch, verify that the switch works, verify light green/red at the wiper switch has power when the switch is pressed, verify power's getting through the wiper switch to green, and so on, back to the actuator. If it's missing ground, there's much less on that side of the circuit. Just the wiper motor interlock and a couple of body grounds. The whole diagram's on BF-11 of the '90 manual, have a look at that as you're going through it so you can see what connects where.

[Bozer1991]

The wiper switch is 3 stage - left is on, center (presumably) is Off and right is washer fluid. I'm at center position.

 

I don't have the FSM you're referring to, so I appreciate the wiring suggestions @Slartibartfast. I'll start the wiring chase

[adamzan]

I have a working wiper out of my 1994, I could ship it to you.

[Slartibartfast]

The '90 manual is a free download from cardiagn.com. Most of it is the same as the '94/'95 manual on Nico, but there are enough stupid little differences to bother getting the right one.