Now that my crank/no start issue is resolved (bad PCM) I'm checking out the rest of the truck. I have the 4R70W with Borg Warner 4406 TC. 4WD seems to work fine and engages normal, seems to shift into low range ok when stopped, brake pedal applied, in neutral. Issue: when I switch into low range, I get the 4x4 light in the dash, but not the low range light. TC is definitely in low range and can hear elec motor on TC run. Wondering if it is just the "low range" lamp burned out in the dash as neither the 4x4 bulb or low range bulb come on at key on bulb check. Is there a bulb check for those 2 items? Is there an easy way to test the bulb besides pulling the dash apart and removing it? (not sure how tough a job that is...)

 

There are several videos about pulling the instrument cluster.


And you might want to watch this video too.

 

Removed the Instr. Cluster, but no replaceable bulbs for 4x4 or Low Range. There are bulbs on that side for Batt and Airbag plus a larger replaceable bulb for gauge illumination as indicated in pic below. The 4x4 and Low Range indicators are approx where shown in the pic, but must be integrated into the board? How do those lights work?

 

Power to those lights go through the GEM.

 

I put instr cluster back in. I noticed when I start engine, 4x4 light comes on for just a sec. (nothing from low range light). Is that a normal check coming thru the GEM? As I mentioned, 4x4 engagement (both hi and lo) seems to be operating normal, just not getting the low range light in low range. Is there a circuit I can trace to see if GEM is outputting the correct signal to light the low range light?

 

Is there a switch in the transfer case that turns on the low range light in the dash?

 

The case motor has a circuit board and contacts that signal the GEM.
The Gem then turns the light on 'after' it gets the signal, indirectly.
Either the light is out or a connection on the dash board is faulty..

 

Thanks. In my owners manual, I just saw that the low range light is one of the 11 lights that should come on during bulb check. It does not, so I guess that means the light is out. When I had the cluster out, the low range bulb was not replaceable (seems built into the circuit board). So I guess that means i'm looking at replacing the whole cluster?

 

Look at the 4 low light closely.
It should be replaceable.
If the CEL, low oil pressure, and low fuel comes on, the processor that drives these lamps should be good as it drives the 4L lamp as well.
If you go to another cluster, reprograming is involved or the PAT won't work.
No use getting into that expense and hassle for the sake of a Lamp that is out.
Good luck.

 

should be a small led soldered in. like the 4x4 lamp. I had to replace my 4x4 lamp some time ago....

 

Fbird.....this is as far as I got in my disassembly. Is the 4x4 led that you replaced on the other side of this board? The 4x4 lamp and Lo Range lamp would be located approx where shown in the pic above. I assumed that since there were no twist type bayonet lamps like for the gauge illumination that they weren't replaceable. Sounds like I didn't go far enough and look at the other side of the board....

 

reply sent...btw it's been several yrs since i did mine I do recall having to go to radio shack to by an led bulb....it is slightly different in color ...but it luminates

 

Fbird....I see you tried to reply to my PM, but looks like it just sent my orig mssg to you as a quote. Would you mind sending again or just posting your reply here? Thanks!!

 

Just removed my dash. ...to find an adjustable light source for my new tranny temp gauge. ..
The LO RANGE light is a board attached LED...
MY MISTAKE. ..I had to change out the AIR BAG light. ...with is a smaller version 194 bulb...

 

number 37 bulb...IIRC