Posted By: loekey53 aftermarket wiper switch not working after rewiring - Sat Oct 17 2020 02:33 PM
I have a 1949 3/4 ton Chevy Step Van. I just rewired the whole electrical system, with an updated 12+ hot, 12- ground, spade fuse box. That light up when in use. Everything seems working except heater and wiper switch. The heater has a drop down resistor. Which I have no clue how to wire it. The wiper motor (3 wire, hi, low, & park) works when I connect directly to the battery, without the switch. I bought a new 2 speed wiper switch, thinking the old one was bad. I converted the old switch (B= battery?, A= high?, P= park?, & F= fast or low? letters on back of switch) from bullet connect to male spade connector. New switch has H= high, L= low, P= park & B= Battery letters on the back. I attached pictures. [img][/img]

Attached picture Front, Driver side.jpg
Attached picture Back Rt. 2.jpg
Attached picture Fuse Box.jpg
Attached picture Old Wiper Switch.jpg
Attached picture Dropdown Resistor.jpg
Posted By: Jon G Re: aftermarket wiper switch not working after rewiring - Tue Oct 20 2020 10:07 PM
I can't tell from your drop-down resistor how it was made. Often you will have 12v hot leading in and two 6v hot connections coming out (one for lower current the radio and one for higher current the heater motor). My guess is the terminal to the left is 12v+ and each of the two terminals to the right are 6v+, but without seeing it I could only guess which would be higher amp and which would be lower amp.

On your windshield wipers, are you sure you're getting power to the switch? This should be pretty simple if the switch has power. You're comfortable with how the park circuit works, yes?
I'm certain power is getting to the switch. The drop down resistor I think the terminal on right of the picture is 12v and the 2 terminal on the left are 6v. I'm not sure how to wire it up and to where. If I really need it. Don't understand if it's important. Can't find any information about the use of it. The wiper switch picture the top terminal is P. The 2 in the middle the left is A the right is B. The bottom is F. Not sure how to wire. Tried a new wiper switch wired hot to B (Battery) terminal and put 1 Yellow wire from wiper motor to H (High) terminal 1 Green wire to L (Low) terminal 1 Black to P (Park) terminal and it doesn't work. When I wire the wiper motor wires to the battery, the Yellow wire is High side. When I put both Green and Yellow wire together to the battery the wiper motor goes to low speed. The Black wire sparks but don't notice any other affect. So I'm assuming Black wire is Park. Wiper switch and 2 speed heater are the only items that aren't working for me after rewire.
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