ShadetreeSeattle
Member
- Joined
- Feb 21, 2017
- Messages
- 42
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Having a tough time with this one, pretty decent at electrical troubleshooting, I have the ford FSM/EVTM for 1990 F series trucks. (mines an 88, but close enough) I have to be missing something here. Pinpoint tests told me to replace wiper motor, did that and it performs same as original motor, they do the same thing. replaced the dash switch, same thing. played with combinations of original switch and motor. it all does the same thing, consistently.
it's the two plug wire harness harness type motor, where it's got a connector for motor itself and a connector for, as far as I know the park switch on the motor basically. (it has the intermittent wipers module with the standard dash mounted turn CCW for intermittent wipe, turn CW for Low/High) not the column mounted switch, idk when they moved off to that setup. i think 94.
The problem:
something has gone wrong in which the switch body is going live 12v, which shorts out if mounted in dash. I accidentally found this out, playing with it while installing the new switch. it only however works at low speed, and only when switch in the high speed setting.
it also only will work with the intermittent module bypassed, directly connecting the switch to the wire harness connector. if the intermittent module is connected, it shorts out and i get wipers which work for like 20 seconds, at the same, low speed then the circuit breaker in the switch starts tripping, giving me. well... intermittent wipers, at the decision of the circuit breaker which really sucks if you live in washington lol.
Side note, i drove this rig all the way form san diego like this, it was not fun haha. if i jumper the blk/light green +12v to either the low or high speed circuits it works just fine. i literally ran two wires from the switch socket and jambed them into a crevice in the dash paneling. i pinched the wires toghter to intermittently operate, twisted them together to run at low speed.
it seems that the low and high speed work fine, but perhaps its something in the park circuit which is shorted? been pulling my hair out on this one. i don't think i metered enough stuff, it's likely something obvious. original wire harness seems unmodified, but that doesn't rule out much. i think after writing this that i need to go thru and check everything for shorts again, something is getting shorted when its suposed to be 12v. the weird part is that if directly jumpered at the switch harness, both low and high speeds work fine, no shorting, no overcurrent, barely even spark when i plug the wire in, as expected. ***? lol. halp. thanks all.
it's the two plug wire harness harness type motor, where it's got a connector for motor itself and a connector for, as far as I know the park switch on the motor basically. (it has the intermittent wipers module with the standard dash mounted turn CCW for intermittent wipe, turn CW for Low/High) not the column mounted switch, idk when they moved off to that setup. i think 94.
The problem:
something has gone wrong in which the switch body is going live 12v, which shorts out if mounted in dash. I accidentally found this out, playing with it while installing the new switch. it only however works at low speed, and only when switch in the high speed setting.
it also only will work with the intermittent module bypassed, directly connecting the switch to the wire harness connector. if the intermittent module is connected, it shorts out and i get wipers which work for like 20 seconds, at the same, low speed then the circuit breaker in the switch starts tripping, giving me. well... intermittent wipers, at the decision of the circuit breaker which really sucks if you live in washington lol.
Side note, i drove this rig all the way form san diego like this, it was not fun haha. if i jumper the blk/light green +12v to either the low or high speed circuits it works just fine. i literally ran two wires from the switch socket and jambed them into a crevice in the dash paneling. i pinched the wires toghter to intermittently operate, twisted them together to run at low speed.
it seems that the low and high speed work fine, but perhaps its something in the park circuit which is shorted? been pulling my hair out on this one. i don't think i metered enough stuff, it's likely something obvious. original wire harness seems unmodified, but that doesn't rule out much. i think after writing this that i need to go thru and check everything for shorts again, something is getting shorted when its suposed to be 12v. the weird part is that if directly jumpered at the switch harness, both low and high speeds work fine, no shorting, no overcurrent, barely even spark when i plug the wire in, as expected. ***? lol. halp. thanks all.
