You can get new switches for under 20 bucks. Check amazon, or Wal-Mart as graveyard said. If you can't find one for 20 bucks (which I'm positive you can if you're in the U.S.) I'll send you one of mine for 20$. Not sure on the testing procedure for tccm.

 

There is an easy and simple fix to this that does not take long to repair. Atlleast it was very easy to fix this on my 1999/2000 Blazer ZR2
I had the same problem on my 1999/2000 Blazer ZR2 that the 2HI - 4 HI - 4 LOW and AUTO 4 WD that the diodes did not illuminate at all

This is what i did to fix this:
Take the switch out by just using your fingers and take the connectors off.
Then open the switch by taking off the cover and use electro cleaner on the contact points on he switch and put it back together again

If the diodes still does not light up properly take it out again and resolder the solder points on the backside of the switch.

I tried first to clean the contact point using electro cleaner on my car and that worked for about 3 weeks before the diodes started to cut out sometimes

This is a couple of years ago and the switch is still working as it is supposed to after i resoldered the switch :-)
So i took the switch out again and resoldered the soldering points on the backside of the switch.


The picture to the left:.Shows the connectors you have to take off on the backside of the switch
The picture in the middle:. The red arrows show where you carefully pry open the cover on the switch
The picture to the right: Here are the 4 soldering points you need to resolder shown with a pen on the picture
The picture to the far right shows the light diodes circled in red that are for the different "drive" programs


Hope this is of help :-)

 

Interesting fix. Was any of your lights working on the switch before you had to fix it? I have no lights on mine but when the driving lights are turned on after dark, the switch itself illuminates but not the diodes to signal what 4x4 mode Im in.

Does anybody know what feeds the lights on the switch? Is it the trans case module in kick panel or something else?


I have more urgent problems now. It failed the emissions test or at least it will. I had cleaned some grounds up, and had the battery out. I guess it had not driven enough since hooking back battery because when I went for test, it came up not ready. I have to go for re test, but my code reader shows flashing evap with no code present. The only code for sure that comes up is ABS. Without throwing parts at the problem, I would like to diagnose it first. Its either the charcoal canister under the driver rear frame or the evap purge valve which I replaced already several years ago.

 

I had 1 diode working sometimes only. When you put the ignition on all of the lights in the drive mode switch are supposed to light up for a short while.
I am pretty sure that if you only clean the contact points as shown on the picture below (see the red arrows) you will have light alleast for a while in the diodes. It worked for about a month and then i had to resolder the contact points.
The switch is easy to take out and easy to open. It is a 5 minute job

It might also be if you take out the switch and try to wiggle the connectors while they are connected to the switch you might see the choosen drive program diode light up and go out again but you need to atlest clean the contact points using electro cleaner on a q tip

Think of all that are having problems with their remote key fob and they change batteries and that does not help. You have to open the key fob and clean the contact points where the buttons on the key fob touch and clean them with electro cleaner as well.
Almost non of the switches in my car worked when i bought it and all i did was to open them and clean them using electro cleaner and i have never had a problem after i did that and this is several years ago

 

Thanks Saint,

I tried cleaning... no luck. Before I buy the trans module, I wanted to test it. How would I test the connector and module? Use a Voltage meter? Groundout on the frame and then each prong? What reading am I looking for? Thanks.

 

A free option would be to clear the TCCM codes. Remove the 10 amp courtesy lamp fuse from the interior fuse panel for 10 minutes and replace. Then cycle the key from off to run and back off without starting the truck 5 times. All the amber button lights should flash.

 

Here's some more info, although 1995 does not have a BCM like the 2001 does so there might be some minor differences in the wiring. https://blazerforum.com/forum/2nd-ge...-blazer-89670/

Note there are four fuses. ATC, Courtesy, 4WD, Illumination. The first three are most important. They can be functionally checked at either the TCCM connector or the 4WD controls connector.

ATC fuse is likely to blow with a bad encoder motor and/or possibly TCCM. It is in the underhood relay center. If it is blown and no corrosion of the wires at the TCCM, replace the encoder motor. Then if still no worky, replace the TCCM too. Keep in mind that a bad encoder motor can take out a new TCCM.

There is no way for you to check a used TCCM, other than it operating the 4WD correctly. I personally would never screw around with a junkyard TCCM. Applications can be very specific. Cardone ones at Summit or Rock Auto are not that expensive.

Again, IMHO very doubtful that control buttons are the problem. MAKE SURE YOU HAVE POWER TO THE TCCM AND THE BUTTONS, ON ALL THE RIGHT CIRCUITS BEFORE DOING ANYTHING. If you want to test the buttons, you can do that at the TCCM connector using a digital volt meter.

Kinda makes you wish for a good ol' manual lever, right?

 

That's a lot more info. Thanks Les. You look good in green.

 

Thanks for all the tips. I am trying to figure out as I go here. My disagnostic skills are `lacking. I grounded out pin 13 and no lights come on the 4x4 switch. I took a chance a bought a working TCCM today and no difference. No led lights come on at the dash switch. I hear no clicking sounds from thr transfer case motor and all the fuses are good.

What feeds the lights at rthe switch? If no lights are on and its stuck in 2hi then what could it be? Vaccum lines? Transfer case vaccum switch? What feeds those lights. I have cleaned the dash switch. LED,s and the connections looks clean and intact. Frusrtation setting in. Can there be any ground wires I missed that is stopping the dash switch from lighting up? I cleaned the two under the battery tray. I get the whiter lights that illuminate around the circumfrance of the dash and dash switch, but not the collored LED,s that show what mode the transfer case is in. What the heck feeds those lights?

Thanks for info LES,

How to properly hook up the volt meter? Black term to ground in the plug itself and test each of the other pins or ground out to frame somewhere and test each pin in the TCCM harness? Thanks,.

 

OK - First lets start by establishing what kind of 4WD system you have. 3 button or 4-button? The four button has an extra button marked "Auto". It is a completely different system with completely different wiring and diagnostics. I'll tell you what pins/wire colors to check on the connectors if you like, but first need to know what system you have.