wiper wackiness....need help!

[83 chif]

the wiper motor on our truck seems to be getting a constant flow of more than 30 amps, even when there is no key in the ignition. we have the truck completely off, and the wiper switch is even in the off position, and we try to put in a 30 amp fuse, and it immediately blows. why and how is the wiper motor constantly getting so much power and how can we fix this? is it a voltage regulator problem? thanks for anything you can tell us.....

 

[corax]

have you tried the simple route of replacing the wiper motor yet?

disconnect the wiper motor connector and see if it still blows the fuse . . . if it does, then you have a short in the wire harness somewhere between the fuse and the wiper motor. You'll need the wiring diagram to diagnose and probably the help of someone who is good with electrical.

 

[83 chif]

wiper motor

yea, the mess actually started after we replaced the wiper motor. and the fuse blows with the motor unplugged and the ignition completely off.

could we run a new wire from the batter to the fuse box and by-pass the old shorted one? where would we need to run it so that it doesn't get contant power? from the battery to the regulator to the fuse box?

yup, you guessed it, i am not an electrical engineer

 

[Jukelemon]

Why was the wiper motor replaced in the first place? I guess my point is that logic states to look for the variable that changed and then find the connection.

Are you positive the old wiper motor was bad i.e. did you bench test it? Perhaps you started with a harness issue in the first place and thought otherwise?

 

[corax]

could we run a new wire from the batter to the fuse box and by-pass the old shorted one? where would we need to run it so that it doesn't get contant power? from the battery to the regulator to the fuse box?

if you can find a wiring diagram and post a link or picture of it I could tell you which wire you would need to run . . . it would have to be the wire after the fuse, possibly through a relay or through the switch (not sure on the layout, that's what diagrams are for )

 

[Jukelemon]

Guys, why bypass a failed harness? Essentially, what you are doing is creating a parallel circuit to a known, bad circuit.

Nothing is going to happen other than the same thing with an additional wire. Harness will short out regardless.

Find the issue in the harness and repair.

 

[Bogo]

It sounds like there may be two problems. The wiper circuit is getting power when it shouldn't, and on the other side of the fuse is a short to ground. Have varmints been chewing on the wires?

You are saying the fuse blows even when the ignition is off? If you have a DVM, use the DC voltage function to find out which lead of the fuse is hot? PS, both should be dead. If either is hot the wire to that lead is somehow connected to (+). Start tracing the wires connected to the powered side and looking at them carefully. Check the backside of the fuse box, there may be a foreign object shorting terminals. Also the ignition switch may be faulty and allowing accessories to stay on. One of the wires may be shorted to a positive wire. The wiring diagram indicates that there is no accessories relay, just one of the two armatures in the ignition switch. It is fused for 40 Amps, The '85 FSM shows the wipers has a 20Amp fuse, not 30Amp.

It also sounds like there is a short after the fuse that is causing the fuse to blow.

If you don't have a DVM, use a 12V light bulb and some wires. Connect one end to ground and the other you use to test to find out which fuse lead is hot. I strongly suggest getting a DVM as there are so many things that can be tested with one. A mid line rat shack is all that it takes.

PS, check out the FAQ thread at the top of this group. There are a '85 FSM manual and a '93 FSM linked in it. The wiring diagrams for wipers are rather similar. So likely your '89 is the same.

 

[corax]

Guys, why bypass a failed harness? Essentially, what you are doing is creating a parallel circuit to a known, bad circuit.

Nothing is going to happen other than the same thing with an additional wire. Harness will short out regardless.

Find the issue in the harness and repair.

I do it all the time, run a bypass wire and cut the original wire out of the equation . . . much easier than trying to find the spot in the harness that took 20 years to short (unless it's an obvious short/chaff)

 

[NorCalBorn]

**Meant to be humorous, no harsh jab intended..

[Remote Diagnostics Status: ON]*In honor of Ed's passing away today and remembering Johnny..

(Johnny)The price of bananna's in New Jersey at 3am...

(Ed)Huh???

(Johnny)Like why would it matter the price if you can't buy 'em? Using wipers in the Summer?

Corax's Reply*x2! IMHO it's most likely (as is every time I've sen it on the 1st gen Runners which the O/P has in his/her sig line) the positive side of the switch is shorting out. On that generation just pull off the streering column trim and see if the usual suspect (red wire going to the switch) soldered conection is shorting out on the shaft or other part of the switch board.

May you find your solution in a short period of time and find humor in frustration..we've lost a bit of Americana today..

 

[Bogo]

Corax's Reply*x2! IMHO it's most likely (as is every time I've sen it on the 1st gen Runners which the O/P has in his/her sig line) the positive side of the switch is shorting out. On that generation just pull off the streering column trim and see if the usual suspect (red wire going to the switch) soldered conection is shorting out on the shaft or other part of the switch board.

May you find your solution in a short period of time and find humor in frustration..we've lost a bit of Americana today..

That needs to be in a FAQ somewhere...

 

[WristPin]

Guys, why bypass a failed harness? Essentially, what you are doing is creating a parallel circuit to a known, bad circuit.

Nothing is going to happen other than the same thing with an additional wire. Harness will short out regardless.

Find the issue in the harness and repair.

words of wisdom right there!

anyone *cough* corax *cough* doing this is got it all wrong.

its like stuffin a rag in the gastank instead of buyin a new gas cap

 

[NorCalBorn]

words of wisdom right there!

anyone *cough* corax *cough* doing this is got it all wrong.

its like stuffin a rag in the gastank instead of buyin a new gas cap

..and playing w/ matches and runnin' w/ scissors ;p

That needs to be in a FAQ somewhere...

*I could swear it was in a FAQ somewhere, years ago when I posted up w/ the now defunct login..maybe it got deleted, I'll try to grab a pic w/i the next two weeks so we can add it in, worst case I'll get a pic of a good one and identify the wire. It can also occur with the turn signal switch FWIW..

 

[Bogo]

The reason to trace down the dead spot in the wire is to get all the other nearly dead wires in the area fixed a the same time. Fix it right the first time...