LUVTruck.com

I wanted to install a switch so I could toggle the fan on the vent on/off.
On the motor there are 2 wires, blue and black. They each have male/female plugs that plug into them. I thought I could just run 2 other wires with plugs and have a switch inbetween.
Sounds easy right? Well I happened to have an extra wire that was black and I wasn't sure what it went to. So I installed the switch and fhe fan worked. Then I had to plug the wiper switch back in (had to take it out while installing the new switch) once pluged in, the the night lights over the heater controls came on but no wipers.
So I thought maybe the other wire I didnt plug in was the one I needed. But as soon as I tested it, the same lights on the heater came on again.

Put the toggle switch in the wire going to the fan speed selector switch on the control unit hanging over the tranny hump.

I'll try routing the switch to the wires going behind the heater control.
Then see what happens. I still have the issue of a loose black wire. It goes up to the wireharness behind the Cig lighter/ash tray.

There's a sliding hot strip in the ash tray that turns on a light so you can see where you flick your ashes. It also powers the lighter. If you don't need them or want them, put some shrinkable spaghetti insulation on the end of that wire. It's great for insulating splices or dead ending bare wires. Mcdonnell-Douglas came up with the stuff for the F-4 Phantom fighter that was used so much in Viet Nam. Hey Roadshow Bob, that stuff still around? The Navy flew F-4's.

I ended up using the black wire off the fan for my new switch. (The problem ended up being a connector on the end not crimped enough).
I found that the extra black wire is hot (has power) so I just tapped it for now. There already is a wire hooked up behind the ashtray that give power to the cig lighter. Although I'm still perplexed that my lights above my heater controls come on when the wiper switch is in the off postion.
But at least thats only when the ignion is on or trucking is running.

Robertcda,
that shrink wrap is still around, we use it even on the newest Super Hornet's and the like, but then again it's kinda still a McDonnell Douglas product. It is awesome for insulating wire ends and sometimes even terminal connections. I can highly recommend it.