I noticed that both of these do not work on my truck.. Thought they may share a fuse.

Now, it seems to vary and be specific to each exact model, but, is there maybe a first fuse I can check?

If it's that, then, it will be straightforward for me to change the fuse. This truck works great.

I brought it somewhere with a Power Probe, they confirmed "bad ground" on my Power Windows issue.. Asking about the Cruise/RW Defrost here.

1994 Tahoe LT Blazer 4.3

 

The rear defroster is powered by both the IGN/GAU fuse and the PWR ACC circuit breaker. The cruise also uses the IGN/GAU fuse, however so do a lot of other items that you likely would notice not working if it was blown. I cannot find the appropriate wiring diagram showing the full cruise circuit, but it may have more than one fuse.

The rear defrost also has a timed relay in the mix. You can start at the back of the truck ensuring that you have a good ground on one end of the grid. If you do not have +12V at the back as well when the ignition is on and the defrost is turned on, then your first step would be to locate the relay and test there.


I believe your truck still uses the vacuum powered cruise actuator. If so, the most common problem with these systems is a loss of engine manifold vacuum. Given the trouble you have gone through with this truck in the past, I would highly suspect a missing or damaged vacuum line.

 

I would like to add to swarkks
In my experience with these (have had a few) The tabs on the rear window/window support that send the current for the rear defrosters are known to break, and it is also known to come detached from the window which would cause them to not work. I would check that first.