1993 Thomas Wiper Motor Switch/Harness

[CanadianFramelines]

Hi all,

Having a little wiper trouble, and that's a big deal on the West Coast in March! I've got a 93 Thomas, and it has the individual wiper switches. The left one was always erratic, only working on hi and not parking. The right one was pretty much fine. So I started to dig into it and I assessed that the left switch was not triggering the relay for the intermittent setting, so I decided to replace it and, after ending up from Lordco finally at Inland Kenworth, got a Cole Hersee 75600-02 single motor switch.

The new switch has six wires, and the harness on the bus has 8 slots for both motors. I assumed that one was hot, one was for the washer pump, two were for the left hi and lo, two for the right hi and lo, and then presumably park for each. I tried to hook it up this way and got the pump working, and the motor would work on lo and hi, but no intermittent and it wouldn't park. Then, after some more trying, the switch quit working altogether. Hope I didn't fry it but it seems that way.

Anyone know what might be happening? I feel like this switch might not be appropriate, because it's definitely not the original based on the wiring I found when I opened it up. Any info on the switch, harness, or motor original to the bus would be very helpful, thanks!

Ryder
Canadian Framelines

 

[chev49]

i would simply take the switch back, along with the original one and try to have them match up the right one...
my bus has the same switches... you can also contact the thomas people as they have a parts department, and should have the correct switch for you.

 

[CanadianFramelines]

As it turned out, the problem was both the switch and the motor. So for future reference, a good switch is the CH that I mentioned before. And I don't remember the part number for the motor itself but could probably get it. I went to International to talk to them, and they referred me down the street to Peterbilt! Luckily all the truck stores here in BC are in one convenient row in Port Kells. PB got me a motor for 90 bucks after tax, and it fit well.

The only issue is that wiring between the switches and motors seem to often be proprietary and incompatible. The easy things are, on the switch: 12VDC, ground, washer pump, lo speed, hi speed, and park. On the motor, there are: lo speed, hi speed, ground, park (blue), and one other that I couldn't figure out for a long time until I realized that in order for the park circuit to work in this arrangement, the motor has to have independent power. So that last one is another 12VDC.

 

[bus-bro]

Cool.