88 GMC 4wd not working?

[A-2 ace]

I have a 88 GMC that's not wanting go into 4wd!?! It would go into 4wd when I got the truck and today no dice!! It feels like the transfer case is work it's just not locking the front? The light on my floor bored don't light up either??

 

[skylark]

I have a 88 GMC that's not wanting go into 4wd!?! It would go into 4wd when I got the truck and today no dice!! It feels like the transfer case is work it's just not locking the front? The light on my floor bored don't light up either??

There is a thermal actuator in the front diff, it is crap. Use a posi lock and back happy for the rest of your life.
https://www.summitracing.com/parts/...J0Zj1xYVcwEE1CDeTmRYERU95xutOT2saAis3EALw_wcB

 

[A-2 ace]

@skylark RIGHT ON!!! Thanks for the link man!!!

How did you mount you're switch?

This came of the description on the link (an added bonus, a 2WD low-range to give you the rear-wheel torque of 4-LO, and the bind-free steering action of 2-HI.) Have you used this before with you're install?