Wiper Wiring Question

[Rick Williams]

The manual has you splice the Painless door lock power into the yellow wire to the wiper switch. What's wrong with using the wiper power that's already in the Painless fuse box? Is the Painless wiper power used for something else? The only thing I can think of is that the donor wiper motor needs more than 15A, 16 gauge, which is what is provided from the Painless wiper motor power circuit. Door lock power is 20A, 14 gauge. The issue I have with doing it the FFR way is that door lock power comes from B+ on the Painless harness so if you use it for wipers, when you turn the car off with the wiper motor on it will keep sweeping. The 15A Painless wiper power comes from ignition so the wipers won't operate if the car is turned off which is how it should be. The other issue I have is that I want to use door lock power for one of the windows. I keep reading that the power window fuse blows if you try to close both windows simultaneously so I want to put one window on the power window circuit and the other window on the door lock circuit. So...Does anyone see a problem with using the Painless wiper power instead of using door lock power? Is 15A enough for the donor wiper motor?

One other comment but I figured it out. The manual has you cut the pink wire about a foot from the donor wiper switch plug and then has you go back and cut more pink wire and splice it back in. What???? Why not cut it about five feet back so you don't have to splice it back in? That's actually what I did. Then the manual has you leave the pink wire dangling with no explanation. After doing some continuities with the wiper switch I finally figured out that the pink wire is +12V feeding the washer motor. I went to the washer tank/motor installation section and couldn't find anything related to electrical connections. It has the tubing connections explained and then it pretty much says "test it out." Maybe I missed something but I don't think so. Sometimes FFR cracks me up :D.

[Rick Williams]

I got lazy and asked a question before I did enough research. After finding the wiper/washer schematic in the Vette manual I found out that +12V to the wiper switch is fed through a 25A fuse. I guess the Painless 15A wiper power with 16 gauge wire won't cut it. I still want to preserve the door lock circuit so I'm going to use the supplemental fuse box I've already installed and run a 25A feed to wiper/washer power. Problem is, I'm back to one of the issues I had with FFR's solution of using door lock power. My supplemental fuse box is wired to B+ so when I turn the car off the wiper will still sweep. Oh well, it's not that big a deal to turn off the wiper when I realize it's still going.

[GII351]

I did not use the painless wiring or a donor car, but my question is why can’t you just replace the 16 gauge wire in the painless harness with a 14 and replace the 15amp fuse with a 20 or 25? (20 is sufficient) No extra parts and a clean source of ignition on power.

[Rick Williams]

I did not use the painless wiring or a donor car, but my question is why can’t you just replace the 16 gauge wire in the painless harness with a 14 and replace the 15amp fuse with a 20 or 25? (20 is sufficient) No extra parts and a clean source of ignition on power.

It's maybe doable but it's not that easy. I'd run the risk of damaging the fuse box. There's a bus bar imbedded in the fuse box with integral crimped connectors for each circuit powered from ignition. I'd have to figure out how to remove it, uncrimp the wire for wipers and re-crimp with a 14 gauge wire. It's probably not worth the risk plus I've already got other circuits run and would have to remove all my wiring just to remove the fuse box. No biggie. I've already installed a six circuit supplemental fuse panel. I'll run a 20-25 amp circuit with a 14 gauge wire from it.