Posted By: roadrunninMark
Possible to test 3 speed wiper switch? - 04/24/23 01:07 AM
I got a 3 speed switch, 378, and was wondering how to test it to make sure it works correctly. Anyone have know how to do so? Do you need a 3 speed wiper for testing the switch?
Posted By: PhillyRag
Re: Possible to test 3 speed wiper switch? - 04/24/23 02:01 AM
Shop manual wiring diagrams have the info.
Posted By: ns1aar
Re: Possible to test 3 speed wiper switch? - 04/24/23 03:32 AM
My Mopar has them for download
Posted By: second 70
Re: Possible to test 3 speed wiper switch? - 04/24/23 03:14 PM
Here's a test for an ebody variable speed. Not sure if it's the same but I'm guessing it is. 0 means 0 ohms
Mike
Posted By: EW1BH27
Re: Possible to test 3 speed wiper switch? - 04/24/23 07:44 PM
AFAIK a "378" is the same as a "380" (variable speed switch). The following is a re-written white paper (PDF) by Slotts of JS Restoratoins .
2770380 Wiper Switch Testing
A = Brown w/ White (Bulkhead Terminal Position 1)
B = Pink
P = Blue (Bulkhead Terminal Position 5)
W = Brown (Bulkhead Terminal Position 19 – Washer Pump Motor)
F1 – Red (Bulkhead Terminal Position 2)
F2 = Green (Bulkhead Terminal Position 6)
B/U = No Connection
B to B/U = B voltage in across the internal circuit breaker.
Always on no matter what speed or off position to B/U. B/U Voltage After Circuit Breaker
The following connections should all be reading 0 ohms, except as noted, when active. Any connection combination not mentioned should not show a reading. The switch body must be grounded from side ground strap to -12v if being tested without the switch panel secured in the dash with all four screws.
In the OFF position:
B to P
A to F2
F1 to Chassis Ground
In On Low through High speed positions:
B to F1 {(0 Low) to (25 High)}
A to F1 {(0 Low) to (25 High)}
B to A
F2 to Chassis Ground
Washer Motor On – No Reading In The Off Position:
B to W
A to W
F1 to W
Posted By: roadrunninMark
Re: Possible to test 3 speed wiper switch? - 04/24/23 10:16 PM
Thanks for the info. I will give it a shot.
Found this Youtube video on how to repair a switch (if gummed up with dirty connections).
https://www.youtube.com/watch?v=CLm2OkRWV5s
Posted By: EW1BH27
Re: Possible to test 3 speed wiper switch? - 04/25/23 12:40 PM
I've had success rebuilding them. That video didn't address the the side terminal that you'll have to unsolder.
Posted By: roadrunninMark
Re: Possible to test 3 speed wiper switch? - 04/25/23 02:10 PM
EWB1b - yes, no mention of that, maybe that is the "lug" that he tore. Is unsoldering that one piece straight forward?
Posted By: EW1BH27
Re: Possible to test 3 speed wiper switch? - 04/25/23 05:45 PM
Yup very simple. It's the silver piece in the middle of my picture, it's soldered to the outside of the case. I was surprised how little heat it actually took considering the case is a huge heat sink. I thought he broke off one of the tabs (dinks) that had to be straightened out/bent back to open up the switch. Like he said be careful with that, they're pretty soft. I had a tab/(dink) crack as I put it back together. At least it didn't break completely off.