Hey fellas i have a 99jimmy that's giving me fits i paid someone to put a good engine in it which has been rebuilt and runs great the truck is in good condition but ive been having electrical problems since i got it back the sunroof stopped working after i opened it the ac doesn't work when commanded and now the auto trak 4wd stopped changing modes and none of the lights work any more im wondering if there's a common ground point that could cause all of the issues ive seen some intelligent responses here so im hoping someone has some advice for me sunroof I can live without but 4wd and ac are a necessity please help im disabled and tired of being broke all the time

 

Well, I'd say it may depend on how they dealt with Your engine swapping. If, for example, they used a crane instead of vertical hoist, they were probably forced to dismantle the A/C condenser from a radiator support and the support as well. That makes Your A/C system empty, and it won't start for safety reasons.
As for the 4WD drive mode You may have a problem with the vacuum lines.
Have You had these things working on right after You've collected Your ride after an engine swap?

 

I shouldve been more clear this truck was purchased with a locked up engine because i had a blazer of the same yr model which was totaled by an innatentive driver while parked. The drivetrain and suspension parts were new so i found a suitable donor for the parts, this is where the engine came from. the oil pan was destroyed in the blazer but the one in the jimmy was good so i swapped oil pans and paid someone to do the engine swap, the jimmy is an slt model which means auto trak 4wd sunroof and computer controled climate system, the ac was discharged during the swap but as i have access to ac equipment i have replaced the necessary components evacuated and recharged the system, however it will not command the compressor on. i can jumper the relay to force the clutch on but not getting the command from the ccc module, sunroof quit within a week of getting the truck back and then the 4wd started acting up. at first it wouldn't go into 4wd so i tried using ahand held vacuum pump to actuate the front axle which got it into 4 hi so I tried 4 lo, heard a loud thunk under the truck which i assumed was the tcase as it shifted to 4lo as evidenced by the light remaining on the next day i got in and tried putting it back in 2hi and it refused to shift back. light blinks for a few seconds and goes back to 4 hi on solid. now its displaying a service 4wd mil and none of the lights are on they blink when i first start the truck so i know they can work just aren't being told to come on

 

My appologies for any misspelling or grammar that isnt on point im doing the best I can

 

It's very hard to read, not because of grammer or spelling, but because there's no periods to define the end of a sentence. Perhaps you could edit it and put some in.

 

Check the grounds on the back sides of the heads between the engine and firewall.

 

Thanks for the very valid input. Those grounds are suspect in that removing the blown engine my father and I neglected to remove them from the old motor and pulled them off with the motor the mechanic who did the swap claims to have put new terminals on the wires and since they are nearly impossible to see i havent been able to verify that can anyone confirm that those grounds are involved in the circuits im trying to repair?

 

As far as I know those are your major interior body wiring grounds, Your mechanic may have missed one or two. Maybe use a handled inspection mirror along with a flash light to take a peek back there.

 

Thanks odat my disability makes it hard for me to contort myself in such a way that I can repair anything like this but if it keeps me from having to replace hundreds of dollars worth of electronics ill find a way

 

Well, I don''t know if You've been already diving behind the engine block to check the grounding wires, but it is always wise to remember, that every wire has two ends. You don't have to do the uncomfy work behind the heads[1] - You may also check if the not working devices have a proper ground at their edns. Just by checking the conductivity to the chassis.

[1] Unless You find the ground connector missing - then You'd have to ...