wiper fuse blows when key is on

[ghostriders]

Done alot of reading on the wiring of the windshield wiper system. Coolermans write-ups are good. I have followed all advice given and still can't isolate my problem. So I must be missing something. What I have is a 74 FJ40. Everything electrical works except for the wiper system. As soon as I turn the key on the fuse blows. Thought it was a faulty switch, motor etc. So I have disconnected everything. Switch is disconnected. Disconnected the harness that comes from the windshield to the connectors under the dash. Still same problem. Beginning to think I have a problem in my fuse block. I am getting a good ground and good continuity through all the wires. I am getting 12V to the fuse block (blue/red wire). Think I have explained everything. Let me know what I am missing please, Thanks Dan.

 

[bsmith123]

Pull the fuse and shoot continuity to ground on the power wire (chafing to ground)
(Power shorted and going to chassis ground)
then shoot the power wire to the wiper speed wires to look for a wire to wire short
(Power going to ground via short into wiper lo or wiper high wire) But ground is via the switch---are all the wires disco'd?

if the windshield connector is disconnected and the switch is disconnected and you are still blowing fuses seems like all that is left is the power from the fuse box to the common on the motor---motor side should be okay since you discod that.

disco that power wire to the wipers and see if it still blows, What else is on the same terminal at the fuse block as the wiper power wire? You haven't got another wire on there touching ground do you?

that should get you started

if I remember the schematic right power comes straight from the fuse
and Power only runs through the switch for Park
but if you disco'd it, the switch is out of the pic for now

 

[ghostriders]

all wires are disconnected. I will play with that for a bit a report back. Thanks

 

[ghostriders]

Alright. Disconnected power wire to fuse block. Checked for continuity to ground and am good there. Probed the solid blue wire on the other end of the fuse and checked for continuity to ground and I have continuity to ground. That wire, I believe is the power to the switch, and should not be grounding out. Thoughts?

 

[ghostriders]

Well I feel kind of stupid. But thanks bsmith for pointing me in the right direction. I looked at my schematic and followed that solid blue wire. It does two things. Goes from fuse block to washer motor. It also gets taped into by a blue wire for the radio. So went hunting for that wire and I had stuck it to the back of the cigerate lighter. The spade I stuck it to is for ground. Disconnected that wire and no more blown fuse. Just have to put it all back together now to see if wipers work. Will let you know, dan.

 

[bsmith123]

good news

Good News, seems to be the season for wiper probs