Testing an encoder motor? No error codes, good TCCM
#1
01-25-2014, 02:56 PM
Testing an encoder motor? No error codes, good TCCM
1998 Blazer with 3 button 4wd
I've had intermittent 4wd problems for a while now. Previously, my 4wd lights would blink dimly and intermittently but would usually engage into whatever mode I wanted up until last year when it became progressively worse. I replaced the TCCM and now my lights work perfectly and I can hear the TCCM click like it used to. The problem now is that it won't switch ranges or modes. The light for whatever I select will flash for about 10 seconds and then go back to 2wd. There are no sounds from the encoder motor during this process. I have no stored codes and can't find any other test to try on the encoder motor. All fuses are good. I also have no vacuum related problems that I'm aware of (good HVAC vent control). I thought I had previously read some different posts on guys having similar problems but I can't find them when searching. I was hoping there was some kind of resistance readings or voltage test I could run on it. Probably covered elsewhere but I can't find it.
I've had intermittent 4wd problems for a while now. Previously, my 4wd lights would blink dimly and intermittently but would usually engage into whatever mode I wanted up until last year when it became progressively worse. I replaced the TCCM and now my lights work perfectly and I can hear the TCCM click like it used to. The problem now is that it won't switch ranges or modes. The light for whatever I select will flash for about 10 seconds and then go back to 2wd. There are no sounds from the encoder motor during this process. I have no stored codes and can't find any other test to try on the encoder motor. All fuses are good. I also have no vacuum related problems that I'm aware of (good HVAC vent control). I thought I had previously read some different posts on guys having similar problems but I can't find them when searching. I was hoping there was some kind of resistance readings or voltage test I could run on it. Probably covered elsewhere but I can't find it.
#3
01-27-2014, 07:54 PM
That is an excellent write up but I don't have any codes stored.
Does anyone know what kind of voltage I should see coming out of the harness to the encoder motor? I had approximately 5 volts to 3 or 4 of the pins and the rest were dead.
Does anyone know what kind of voltage I should see coming out of the harness to the encoder motor? I had approximately 5 volts to 3 or 4 of the pins and the rest were dead.
#4
01-28-2014, 06:20 PM
did you read page 7? there it states 4.8-5.1 V
Last edited by sky_blazer; 01-28-2014 at 06:22 PM.
#5
02-09-2014, 01:21 PM
I skimmed over the entire article but that didn't click with me until reading it a second time.
I've been crazy busy with snow plowing and have had no time to work on it let alone post about it. I ended up taking the motor off and charged the heavier gauge black and red wires at the motor. The motor turned fine going in either direction based on which wire I charged or grounded. I then reinstalled it and everything is working fine. The only thing I can come up with is that the motor was stuck but I don't see why directly charging it would free it up.
I've been crazy busy with snow plowing and have had no time to work on it let alone post about it. I ended up taking the motor off and charged the heavier gauge black and red wires at the motor. The motor turned fine going in either direction based on which wire I charged or grounded. I then reinstalled it and everything is working fine. The only thing I can come up with is that the motor was stuck but I don't see why directly charging it would free it up.
#6
02-09-2014, 05:46 PM
Originally Posted by skidud
1998 Blazer with 3 button 4wd
I've had intermittent 4wd problems for a while now. Previously, my 4wd lights would blink dimly and intermittently but would usually engage into whatever mode I wanted up until last year when it became progressively worse. I replaced the TCCM and now my lights work perfectly and I can hear the TCCM click like it used to. The problem now is that it won't switch ranges or modes. The light for whatever I select will flash for about 10 seconds and then go back to 2wd. There are no sounds from the encoder motor during this process. I have no stored codes and can't find any other test to try on the encoder motor. All fuses are good. I also have no vacuum related problems that I'm aware of (good HVAC vent control). I thought I had previously read some different posts on guys having similar problems but I can't find them when searching. I was hoping there was some kind of resistance readings or voltage test I could run on it. Probably covered elsewhere but I can't find it.
I've had intermittent 4wd problems for a while now. Previously, my 4wd lights would blink dimly and intermittently but would usually engage into whatever mode I wanted up until last year when it became progressively worse. I replaced the TCCM and now my lights work perfectly and I can hear the TCCM click like it used to. The problem now is that it won't switch ranges or modes. The light for whatever I select will flash for about 10 seconds and then go back to 2wd. There are no sounds from the encoder motor during this process. I have no stored codes and can't find any other test to try on the encoder motor. All fuses are good. I also have no vacuum related problems that I'm aware of (good HVAC vent control). I thought I had previously read some different posts on guys having similar problems but I can't find them when searching. I was hoping there was some kind of resistance readings or voltage test I could run on it. Probably covered elsewhere but I can't find it.
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