Thank you for adding me, great forum and i hope i will be able to contribute and help other in the near future as i just got a 99 Chevy Blazer LT model 4 doors. Looks really good, but the previous owner destroyed that poor vehicle.

I am in the process of fixing her up as there is tons of issues with it.
i just recently worked on fixing up the rear breaks as the previous owner worked on it, but put in the calipers backward, rear brake lines were cut, all suspensions were busted. so last week end, i fixed the rear brakes and put in the new suspension.

This week end is a massive work to it.
- New fuel pump and sender unit "fuel gauge not working as the previous owner ran out of fuel a few times"
- new cooling system. new rad and new water pump and will flush the heater core as there is no heat, the fan is working.
- new ignition system
- new front suspension

>>>> and this is where i need help from you guys.
the 4wd system is not engaging at all. when i first tried, it was working, but on the 2nd try, i can hear a loud buzzzzzz by the transfer case and my 4 HI keeps blinking when i try to get it to 2 HI.
So last night after work, i took the 4wd switch off and took it apart and took off all the solder joint and put the fresh one in as i know that the resin that gm uses, cracks overtime.
So even after working on this, it still won't engage in 2 HI

some of the youtube video, they claim that you can clean the ground wire hoping to have a better ground for the transfer cases motor to engage, but i can't see the ground wire anywhere on the frame.

So, what should i be looking for to have the 4wd system to work properly?
i haven't got the chance to look for vacuum leaks and should i get a new transfer case motor as they are not cheap, but if i have to get it? so be it.

Thanks to all that can help me out. will post a picture of my new beast later as it is a dark Army blue and gold

THANK YOU =)

 

Welcome to the forum!

Regarding the 4wd system, one of the first things we'll need to know is if it is a 3-button or a 4-button transfer case. The latter has the Auto-4WD feature and.

From your symptoms, I think the issue could be in the transfer case but I'm not an expert on the failure mechanisms located there. I am familiar with how the transfer case control module (TCCM) can fail and how vacuum leaks in the under-hood vacuum hoses can disable the 4wd system.

Have you had the OBD codes read by one of the more sophisticated code readers? There are codes that can be stored that will not turn on the check engine light that could help you diagnose the problem.

Sorry for only giving general advice. Perhaps someone else will be able to give more insight.

 

As for the buttons? i have a 4wd auto, 2hi, 4hi and 4low

when it comes to the obd 2 scanner, i have one on my macbook pro, but doesn't pull any code when it comes to the 4wd system, but i just got another software that is under windows, i'm gonna have to use my Alienware to see what is going on, they claim that the software sees everything.

as for the transfer case or 4wd module, i can hear the module clicking on the passenger side twice and of course the TC motor trying to engage

 

right after work, i crawled under the blazer to replace the fuel pump and all. once replaced, i turn on the ignition and the fuel gauge is still not working.
i looked everywhere online on the fix, and there is nothing. i'll check the wiring again since i'll spend the entire day working on it as i still have to do the cooling system, ignition, front suspension, oil change and see if i can find out what is causing the 4wd not to engage.

 

I found this link for those that might have issues with the fuel gauge. hope this helps some of you with this known fuel gauge problem.

Fuel gauge

 

Well, after a wonderful day working full time on the blazer????? i'm happy to say that the fuel gauge issue has been solved. with the new fuel pump, came a new set of wires which i didn't bother replacing since it looked kind of nice, but this morning?????? i have decided to replace it anyway. What i found was pretty nasty and lucky that it didn't blow any fuse. it turned out that whoever worked on it before, tape the wires to tight, even with the shrink tube applied? well. overtime with vibration, those wire became glued and it turned out the the small gauge ground wire touched a little bit the signal wire "purple" putting the signal to ground. So i replaced the wiring and the fuel gauge is working again.