1998 Tahoe help

[9dreizig]

So I have a 98 Chevy Tahoe that has 278,000 miles on it. I keep it cause it's worth more to me than the market would pay for it.
Recently wouldn't shift into 4 high or low. So I i) put a new transfer case switch actuator ii) put in a new encoder motor iii) put in a new switch
Still won't move now the indicator shows that it's stuck in neutral 2wd and 4wd low all at once!!
Any ideas ??

[fastfredracing]

Id be looking at the transfer case control module . Can your scanner access it ?

[9dreizig]

Originally Posted by fastfredracing

Id be looking at the transfer case control module . Can your scanner access it ?

I have a scanner and it has an ODBII other than checking for faults ( which I have none) what are you suggesting ?

[asphaltgambler]

I believe the motor / actuator on those have a high failure rate, but definitely need to look into what the scanned information tells you.

[berettafan]

This series has issues with the soldering on the switch itself. Related to his wires hang behind it. Pull switch and check connections.

[fastfredracing]

I was just remembering the last time that I got stumped on a similar problem, it ended up being the module was kaput. I was getting similar weirdness from the switch, like showing 2 hi, and 4 low engaged at the same time ( mechanically impossible ) .
I am pretty sure that your module will have to be programmed/coded if you end up having to replace it .
From what I am reading in your post, you have already replaced the switch, and encoder motor, so that leaves, only faulty wiring, or a bad module .
I am pretty sure that a Snap On Scanner, or any decent scanner should be able to read the transfer case module, and see if there are any faults in it . I honestly cannot remember 100% though, that is kind of old.
The last one I did, was in a 2004 truck, but I believe the system is basically the same .
Gambler is correct, that the encoder motors were a common failure part. I have replaced tons of them over the years, but I have also had to replace a few switches, and a module or 2 as well .
You may need a mechanic with a good scanner for this one .

[berettafan]

Doh i missed that you replaced the switch already!

How about checking ground locations for a clean connection?

[speeder]

Unplug it and then plug it back in like a phone or laptop that is going crazy. If that doesn’t work, I’m out of solutions.

[fastfredracing]

Originally Posted by speeder

Unplug it and then plug it back in like a phone or laptop that is going crazy. If that doesn’t work, I’m out of solutions.

Or bang on it ! . I cannot tell you how many times I have diagnosed something electronic, or electric, by tapping on it, or giving it a good smack.

[9dreizig]

Thanks for all the advice,, gonna be a couple days before I get back down to the garage , but I"ll report back!