Cost of replacing body electronic control unit

What body fuse ? The body functions on your vehicle are controlled by three different control module . The IPM - instrument panel integration module ,the DIM - dash integration module an the RIM - rear integration module. Having the vehicle scanned for DTC'S - diagnostic trouble code's should always be the first step in a diagnostic procedure for this type problem . Not at auto zone or advance etc.... they can not pull code's from the body computers . When you push the button for the rear defroster ,trunk release ,these are input's to one of the front modules which will send a message over the class 2 data bus to the rear module which will energize a relay to pop the trunk or turn on the rear defroster . The rear module also controls the interior light's . Your best bet , take it to a qualified repair shop.

Relay maybe . free wiring diagrams here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model an engine size . Under system click Body & accessories ,then under subsystem click on rear window defogger . Click the search button then the blue link .Looking at the diagram you will see three fuse's , a relay ,lighting control module , defroster switch . The switch is a input to the lighting control module , the lighting control module will supply a ground to the control side of the rear window defroster relay ,energizing the relay sending B+ power to the defroster grid.

There is no BODY CONTROL module,but there is a Front Electronic module FEM, and a rear electronic module,REM (not the rock group,LOL!).
The FEM is located behind the driver's kick panel and the FEM is located on the right side down in the trunk.
The REM controls: Rear windows, , all rear lights, trunk opening, fuel door release, rear window defrost grid, trunk ajar switch, front passenger door lock, , front passenger door lock switch,rear door locks, trunk light, fuel pump, fuel level senders, antenna booster.

Hope this helps? don-ohio (:^)

check the rear lighting wire loom from rear of light clusters ,trace the earth wire to the body/chassis connection to ensure a good earth , check for power to the indicater lamp , the bulb holders may be the problem , this is a problem that requires patience as can be hard to trace

change master switch first!

Multi function control switch has to be replaced.

Not sure, but I've heard a bad hazard switch can cause strange problems.
Also, if your truck has a body control module that controls interior and lights, that may be your problem, too. Good luck.

Yeah, I'd think it would have lines, too, unless some new way of doing it that I'm not aware of. Maybe the rear window was replaced with a window without the defrost option. There should be a small two wire connector coming out of the back shelf near lower driver's side of rear window. That would be the defrost connector to the window lines (that aren't there,lol).
Well, good luck with that! I think there are aftermarket kits for rear window defrost, though.

In the passenger compartment: The Fuse no.# 18 (15A) = rear brake lights



If the fuse no.# 18 - F18 (15A) is good, check and replace if necessary the brake pedal switch!

ETACS
(Electronic Time and Alarm Control System)

as far as the rear defroster, it may be the switch, relay, or fuse.

i have all of the service info on mediafire.com , just click this LINK and download whatever you need. i would suggest these 2 sections for fixing your problem:
97-99Electrical.pdf
2gTech_Info_Man.pdf