Service 4 Wheel Drive Message

[emtcee1973]

thats the message thats on my 99 silverado...i replaced the switch(new gm) but still nothing....the switch doesn't even light up...is the a control module for these things under the dash or does the switch act like one???if the actuator on the transfercase were bad wouldn't the lights on the switch still light up???any suggestions would be appreciated...also does anyone have a wiring diagram for the switch and the whole circuit??/how would i go about testing the acuator???

thakns,mike

[emtcee1973]

anyone???

[ZsTB]

I know the vehicles are completly different, but I just had this problem with my 04 Trailblazer. There is a TSB for "Service 4WD Lamp On, No Codes Stored" or close to that, and all they did was reflash the TCM and something else (unreadeable as well as the TSB#). Not had any problems since.

 

Chris

[emtcee1973]

I know the vehicles are completly different, but I just had this problem with my 04 Trailblazer. There is a TSB for "Service 4WD Lamp On, No Codes Stored" or close to that, and all they did was reflash the TCM and something else (unreadeable as well as the TSB#). Not had any problems since.

 

Chris

 

 

thanks chris,what do they charge for something like that???i never had anyone work on my vehicles except me...there are no codes stored by the way......

[millhouse49]

your (tcm) transfer case control module is under the left hand side instrament pannel. just above the dlc conector. they are bad for the terminals being loose. so you can pull the conectors out and plug them back in and see if you get any lights on your switch.

[emtcee1973]

thanks for the info....the last coupleof days the switch lit up,then today its off again...but just a little while ago they were back on...so i would have to assume that it is a loose connection somewhere...i will take alook over the weekend...thanks again...

mike