99 f350 tach/brake problem

I tried to get the tach wire off the instrument cluster, but I couldn't quite get the full dash off, it gets stuck around the radio, im guessing the radio has to be pulled out in order to get to the tach?

Basically all I did was made all my connections, but made no connections to the RS unit. Any ideas?

Any help appreciated.

Yeah, I figured out the brake light problem, now my only wire is the tach, I will try the whie/pink taped to a large bundle of wires next to the parking brake.

When you say parking brake, do you mean right behind the fuse box, where the large harness's come in? I checked the kick panel, theres only about 6 wires going to the back doors running in that loom.

Well, I found the tach wire....

Now heres the strangest thing, the door ajar light will not go out, unless you remove the key from the vehicle.

I unplugged all of the harnesses from the RS unit but the door ajar light will not go out.

Heres the strange part, when I get in the vehicle and start it, drive about 3 seconds, the dome light goes out, but the door ajar light stays on, then when I stop at a stop light, the dome light goes back on, then when I start to drive again it goes back out.

Now I figured it was just possibly feedback from the brake pedal. Well I cut with a snips the brake wire going to the RS unit. No change. Same problem.

I can't understand what the deal is. There should be no problems when you disconnect the harnesses, because it should bring it back to stock.

The only other option is to cut each wire that was sodered and taped... Otherwise everything else on the RS works fine, the only problem is the door ajar/dome light staying on while driving. Any ideas ?