Brake lights
Post by barrman on Sept 6, 2006, 3:10pm

OK, I am planning to switch my truck over from the hack wiring job the fire department (DSPO) did. I still need to drive it 2-3 days a week and don't want to be driving a vehicle that isn't legal.

The DSPO cut off the rear wiring harness above the axle. They just unplugged the front b/o lights. I think my truck last ran with the large blinker box because of the letters on the cut off wires under the hood. But, a small solid state blinker box was bolted to the firewall with the proper pig tail screwed in and about 3 inches of wire. They added an aftermarket blinker set up and just ran all the blinker wires next to the stock wiring.

I got my Packard connectors in the mail today and want to do the swap RIGHT NOW. I already proved with my bench wiring set up that the blinkers and such work. I still have to find the dash end of the 4 blinker wires, but that should be easier once I cut out the DSPO stuff. The only question I have is the brake lights.

http://www.m715zone.com/manuals/wiring/lighting.pdf

I don't know how to copy/paste a pdf page, sorry about that. Anyway, the above drawing shows that wires 75 and 75A are the leads to the brake switch. One is power and the other power back to the 3 lever switch once the brakes are used. I have tried 3 different 3 lever switches and with power in to the "F" lead and the top lever to "Brake light or Service Light." I never get any power to either 75 or 75A. I am doing this without the blinker box hooked up, but that shouldn't matter for this. I think I am missing something simple. Anybody know what it is?

Thanks.