93 S10 blazer 4X4 probs

I have a 93 S10 blazer that has electric 4X4 shift. The only way it will shift into 4X4 is to come to a complete stop put truck in neural and hit the 4X4 low then both lights flash then both lights remain lit then i can hit 4X4 high both light flash again I hear 4X4 module click and front axle engage but I'm not sure of its in 4X44 if I hit 4X4 hi again both lights flash again and I hear the clicks but when u go 2 drive its like its in super super low gear if u don't put truck in neutral and come to a complete stop no matter wat button hi or low u hit nothing will happen thx for and suggestions

I have a 93 S10 Blazer also and as far as I know, you can not shift on the fly. You must stop the vehicle. Mine is manual and is vacuum operated by a diaphram under the battery.

I was able to shift into 4 hi on the move as long as I was under 40 mph mine also uses vaccum I checked that first and changed vac switch on transfercase and checked vac for leaks

Very similar. The transfer case has a few switches on it, which I had to replace on mine, a 4x4 actuator switch and a transfer case switch. The actuator valve under the battery tray, which could have a leaky diaphram. The front axle has a switch also. The control head in the vehicle where you push the buttons. And vacuum lines going to and fro.

Here's a quick look at some things...
http://www.s10forum.com/forum/f220/the-4x4-vacuum-thread-327817/

Thx for the link that will help I put all 4 wheels up and did some checking. The front drive shaft won't turn in 4 wheel high but it does turn in 4 wheel low so I need to check my vacuum I hope I just have a leak somewhere. I should b able to shift into 4 wheel high at any speed or so the book reads but it will only shift while at a complete stop and in neutral and wen it does shift both 4 wheel hi n 4 wheel low indicator lights flash and both stay on no matter if its in 4 hi or low thx for your help

Remove the passenger side kick panel & check the pins on the Transfer Case Control Module, (TCCM) and the connector, for corrosion.... common problem. Clean the pins and sockets and put some silicone dielectric grease on them and reconnect. Could also be a problem with the TCCM itself, or the encoder motor on the transfer case.

I have the tccm down now ill clean connectors and check the pins thx for ur help ill let u no how it goes

I cleaned the male and female ends of connector they didn't look bad but I cleaned em anyway I tried to reset it to with out any luck I read a diff thread that some1 was having the same prob as me an they had 2 replace the tccm I'm not sure if that's what it is but I'm not sure how to test it or the shift motor on transfercase thx for your help.

I found a place that says how to check the 4X4 error codes and what the codes mean I checked it and I'm getting a num 2 code it says that means the encoder is bad and to check wire connections but the only wires I see going to the transfercase is the speed odometer wires I dout those r it but iv been wrong b 4 if any1 knows plz let me no thx for your help and time. This is where I found how to test 4X4 codes and what they mean http://www.s10planet.com/forum/archive/index.php/t-9749.html

When the TCCM commands the encoder motor to shift the transfer case, (either a mode shift or a range shift) the TCCM monitors the encoders position during the shift. Each shift position in the transfer case has a certain "address" called a "count". As the encoder is shifting, it reports the "counts" identifying its position back to the TCCM. When the encoder reports the correct number of counts for the position it was commanded to, the TCCM commands the encoder to stop. If the counts are erratic, or nonexistant, the TCCM determines the encoder is faulty and sets trouble code 2. If vehicle speed is below ~2 MPH, it is entirely possible for the encoder to continue through 4WD HI and perform a range shift into 4WD LO. Check for poor connections at the TCCM and encoder motor. If all appear to be OK, the problem is most likely inside the encoder motor. The encoder motor is located on the driver side of the transfer case, near the output shaft to the front differential. The transfer case in the image below is a manual shift case. The red, round grommet is attached to the shift linkage. On electric shift cases, the linkage is replaced by the encoder motor:

http://i561.photobucket.com/albums/ss58/cwhook/NVG231.jpg

I found where the wires connect to encoder motor I unplugged it and cleaned both male and female w contact cleaner put it back together pulled tccm fuse for 30 mins or so and turned ignition on am off 5 times and started it and it seems to b working right thx for all your help

Good job! If you have trouble in the future, do the same thing to the TCCM connector and apply some silicone dielectric grease to the contacts on the TCCM connector and the encoder connector.

well iv had it working 3 or 4 diff times now it works for awhile then it goes back to doing the same thing error code says transfercase motar im leaning that way but i think the rear seal in tranny is bad i have tranny fuid in my vac line and the actuartor fills with trans fluid i dont know if thats affecting the motar since it seems to be leaking trans fluid from around transfercase motar my transmission fluid gets low in transmission thats why i was thinking it might be the rear seal i think the transfercase is over flowing with trasmission fluid thus the fluid in vac lines an leaking from bottom of transfercase motar thank you for any thoughts and help anyone migh thave

Transmission fluid level going down, transfer case fluid level rising, and fluid in the vacuum lines means one thing.... transfer case vacuum switch is leaking and needs to be replaced. Under $20 and about 15 minutes to replace it. After the switch replacement, get the fluid levels correct, clean the vacuum lines out and you should be good to go. With a little bit of luck, the transmission real seal in the transfer case front seal will seal on their own, just watch the fluid levels. In the image above, you can see the 3 vacuum fittings on the switch. 15/16", 3/8" drive, deep socket and a 3/8" drive ratchet gets right on it. Loosen it up, unscrew it by hand. Dorman part # 600-500, HELP! part # 49315. Most auto parts stores have it in stock.

Remove the passenger side kick panel & check the pins on the Transfer Case Control Module, (TCCM) and the connector, for corrosion.... common problem. Clean the pins and sockets and put some silicone dielectric grease on them and reconnect. Could also be a problem with the TCCM itself, or the encoder motor on the transfer case.

OM, funny thing. A couple years ago my 4x4 stopped working, manual shift. I went through and looked at every sensor, changed a bunch, everything EXCEPT check the connections on the TCCM plug on passenger side kick panel and on transfer case. Mainly because I never heard that was a problem.

I had previously unhooked from the diaphram under the battery and since have use vice grips to hold in 4 wheel high/low etc. It's a PITA, so the connection thing has my interest peeked. Do you by chance have a pic or two of the wires under the dash and the connection at the transfer case?

Thanks.

iv checked and cleaned connectors at tccm and transfer case prolly 8 times sometimes it will work for a day or 2 then its back to doing the samething i was thinking of checking the wires to make sure theres not a short somewhere but i dout it whn i check tccm error codes it says it the shifter motor ill change the vac switch on trans case and check fluids again...ill gets pics when i check connections again and post them thx for all your help

82Stang, are you looking for a wiring diagram, (schematic)?

slp4days, Could be a poor connection that gets moved when you take things apart. I've seen poor crimp connections where it missed the stripped wire and hit insulation along with it during the crimping process.

82Stang, are you looking for a wiring diagram, (schematic)?

Thanks OM, but that's not necessary. I do appreciate you asking though. This is my rarely used plow truck, almost all the way out to pasture. It is on very light duty from now on. It def doesn't look pretty, but 192K and still going.