Any ideas on a box behind parking brake

[johnbuck1987]

i just bought a 2001 f350 lariat crew cab 2wd. 7.3 6 speed. i notices a toggle switch and led light mounted right below the headlight switch on the dash. its a 3 way toggle up position lights red middle and down lights grees. so after chasing some wires i find a box about 6 in tall 8 in wide and 2 in thick mounted behind theparking brake near the firewall. continued chasing wires and it ends up going to the exhaust pipe. so then im confused. the switch doesnt seem to have any effect on power oor lighting or anything that i can tell. any ideas anyone. thanks in advance.

[johnbuck1987]

ok so i cheked this again alot more extenaive. my findings is that the wire to the exhaust is actually going to an aftermarket egt guauge. and the box is some kind of tuner chip. it has three stages. stock then two stages of power i suppose. but its a setup ive never seen before. i cant find any markings or name or number on the box. the way its installed it almost looks factory. but im not sure. any ideas
?

[dieselcrawler]

first off, try this question in the 7.3 general area, more traffic, specific to the 7.3. The box you discribe sounds like the PCM (Powertrain Control Module, I think), it mounts in the area like you said. However, the switch and the LED lights, I have no idea. An aftermarket tuner would attacht to the rear area of the PCM, but none I've heard of are just a switch/LED like you discribe.

Any chance it is a 'jake brake' control, there is a valve in the turbo pedistal that can be wired to act like a jake brake, retarding exhaust for deceleration use...

Good luck, sorry I can't be of much help.

[johnbuck1987]

so the box i described is indeed the pcm. i didnt realize thats where it was located. i assumed in behind the storage compartment. anyway the switch and light is actually a tuner chip. i was told by beans deisel its one of the older diablo chips from when they first started making them. i appreciate all the replys. thanks