Need a little wiring help...

[DennisG01]

I have installed one of those DVD multimedia receivers that does just about everything under the sun. For the back-up camera, there is a wire from the head unit that needs to connect to the reverse/back-up lights. I can splice into the wires easy enough in the back of the truck, but was hoping for something closer to the head unit.

Does anyone know of a wire under the dash that is relatively easy to get to? I'd just prefer to run the least amount of wire necessary.

[DmaxMaverick]

There's a fuse for it, so the fuse box is a lot closer than the rear bumper. There is also a wire in the harness from the NSBU to the PCM, and the PCM to the fuse box. I don't have a diagram in front of me, so I can't tell you what the wire color is. The wire out of the fuse box should be the same as that goes to the lamp holder in the bumper. The wire from the NSBU to PCM to fuse box may be different. A simple test with a V/O meter or test light will help.

[DennisG01]

I didn't even think of checking at the fuse box! Thank you. I did try checking the box that's about where a dead pedal would be. Looked and saw a white wire and some others that were heading toward the rear (at least initially) and got excited (I was hoping they were for the 7-pin trailer connection). But, to no avail - they are all switched + and are live no matter what gear is selected.

Just curious - what is the NSBU?

[DmaxMaverick]

......Just curious - what is the NSBU?

Neutral-Start-BackUp switch. It's the switch that tells the PCM which position the gear selector is in, to prevent starting when in gear, and switch on the B/U lamp. I don't remember where it is on the 1998. Probably the electrical box on the side of the tranny, where the gear selector cable and harness plug attaches to the tranny. That will give you a raw connection for the B/U circuit. The fuse box would be my first choice, though.

[Hubert]

Might want to probe it to see how it works.

At least on the manual trucks a hot wire comes from a shared node (hot when key on run like darn near all wiring) when in reverse gear current can travel to bulbs and are grounded in back at bumper. When not in reverse gear the switch in the transmission opens the circuit.

Anyway I THINK? you would have to splice downstream of the NSBU for switched power I would guess. And the fuse should be hot both sides all the time. I would guess if its similar to the manual trucks (at least I dont think they run a wire back from transmission then to rear lights???

[Hubert]

Might want to probe it to see how it works.

At least on the manual trucks a hot wire comes from a shared node (hot when key on run like darn near all wiring) when in reverse gear: current can travel to bulbs and are grounded in back at bumper to complete circuit. When not in reverse gear the switch in the transmission opens the circuit.

Anyway I THINK? you would have to splice downstream of the NSBU for switched power I would guess. And the fuse should be hot both sides all the time. I would guess if its similar to the manual trucks (at least I dont think they run a wire back from transmission to fuse then to rear lights???

[rhsub]

Power goes from fuse to park/neutral/back up switch on left side of trans then splits and one line goes to lights and other line goes to auto dimming mirror. This would be the wire to look for because it runs up the drivers side "A" pillar (left windshield pillar).This wire is light green and may?? plug into the convience centre under the left side of the dash
Good luck Ron

[DennisG01]

Thanks guys. I'll look for that green wire and probe around a little. If I can't find that easy enough, I'll just go back to the lights in the rear. It'll be just as as easy to go there or the tranny. I've already got a connection there for back-up lights so I'll just open that up and tie in right there. Thanks again!