How to turn your heater core off and on in the cab.

[Waterloo]

(05-19-2019 )earnies2 Wrote:  Thanks I will get that done do you have a wiring diagram?

It was easy, the wiring diagram came with the valve to use with the DPDM switch I posted. I went and looked to see if I still have it, but I think I tossed it... I'll draw one up from memory, it was easy. I'll post below.

You attach the valve, the two wires off of the valve, a blue and red. Red is power blue is ground, they were 18ga, kind of thin but they were tinned at the ends. I had some 16ga wire that I used to run into the cab. I used these butt connectors with shrink tube under the hood... https://amzn.to/2WecARm
The reason I use these particular butt connectors is that the fit nicely in the split loom, no bulging out of the loom, like there is no butt connector under there. I bought the crimper that is used for these, you could probably improvise, but I like tools. LOL... Here is the crimper... https://amzn.to/2HrI12z

I ran the wires through the firewall directly to the switch. There are six contacts on the On/Off/On switch, you need to make 2 jumpers, I used the 16 ga wire, about three or four inches long, one shorter than the other as they cross each other. I used the blue crimp on eyelets, the smallest ones they sell at O'Riely Auto Parts. You will need 6 of those. I used shrink tube on all connections.

I cheated and used those quick connect wire taps to hook to ground and power in the dash. This is a very low voltage valve, only 9 volts required to operate, I did not use an inline fuse. I did not think it was necessary.

I used a 1/2" drill to make the hole in the dash to hold the switch in place.

Here are the wiring schematics.


  Scan May 19, 2019 at 08.40.pdf (Size: 349.65 KB / Downloads: 233)

Side note, attach the valve before you wire unless you are using barb connectors. I had to screw the valve on to a pipe nipple, so prewiring would have not worked for me.