Hey guys. Been lurking for a long time, thought that I would post a big thank you for all of your help with my 1997 Blazer.


I bought it from a rural airport in February 2014, with only 115,000 miles on it (4 door, auto - floor shifter, 4WD). I was told that everything worked as it should and paid $1500 for it, sight unseen. Drove about 5 1/2 hours, each way, in the worst snow storm of the year to pick it up. It was a little hairy towing the trailer up and down the back country hills, but I got home safe.


But getting home was the start of my journey.


Problem #1 was that it didn't seem to be going into 4WD, and the lights on the push button selector didn't light up. I searched and read dozens of threads here, and thought that the TCCM was behind the passenger kick panel, but alas that is the SRS control module. So I was barking up the wrong tree. I finally found the TCCM mounted behind the center dash, wedged in a nearly impossible spot just in front of the floor shifter.


Consulting the wiring diagrams that I located on a thread somewhere on this site, I determined that I didn't have any power to the TCCM. The fuse was good, but the power wire to the TCCM was completely dead. An ohm check verified that it was indeed open, somewhere in the wiring harness under the dash. Instead of cutting open the entire wiring loom and tracing it to find the break, I just ran a new power feed to the TCCM. Voila!!! I had lights on the 4WD selector switch, and the 4WD seemed to work. On to the next problem.

Problem #2 the oil pressure gauge was stuck on max. I figured that it had to be either the sending unit or cluster. I found a cluster on eBay that had the factory tach (mine didn't) and was told that all the gauges worked fine. So I snapped it up. Spent a few hours cracking open the odometer and resetting the 200,000+ mile reading to match the cluster I was taking out. While I had it apart I gave it a good cleaning and it looks brand new now. I installed the new cluster and voila! I had a working tach, but no working oil pressure gauge. So I ran to the auto parts store this morning and picked up a new sending unit (wish I had actually tested the one I had first).

Pulled out the distributor, changed the sending unit, and put everything back together. Fired up the rig and it idled nice and smooth. Guess what? I still didn't have a working oil pressure gauge. The wiring diagram said there was one tan wire that lead from the sending unit to pin 7 on the cluster. Crap, could I possibly have another broken wire? What are the odds???? Took the distributor back out and did an ohm check on the wire. Yep, it was wide open. What the heck is going on?

Let me tell you, splicing in a new length of wire on that sensor pigtail SUCKED!!!!! But I managed to get it done and connected to pin 7 of the cluster connector. Put it all back together, and turned the key. She struggled, coughed and sputtered, but eventually caught and fired up. She was rough for a few seconds, and then idled as smooth as a baby's bottom. But now I HAD A WORKING OIL PRESSURE GAUGE!!!!


But my check engine light was on. Ah ****. Fix one problem and another pops up. P1345 to be exact. I came inside and read a couple of threads on the code and what causes it. I was very careful when I clocked the distributor and made sure that I reinstalled it in the same orientation. So I was thinking maybe another wire broke in the loom somewhere. Then I read where you could mis-clock the distributor and the electronic ignition would adjust timing to compensate. Could I have missed when reinstalling the distributor that last time???? Only way to check was to put the engine at TDC on the number one cylinder and see where the rotor was facing. Sure enough, I was one tooth off the last time I put the distributor in. Pulled it back out, clocked it correctly, and turned the key. She fired up instantly, smooth and clean, and no more P1345.
I am used to working on older, traditional distributors that if you mis-clock them the car either won't start, or will run very rough and not hold an idle. That mine would idle smooth as glass was throwing me a curve ball and I can't hit the curve.


Wow! What a day I have had with my Blazer.


One more problem that I need to address and that is that the AirBag light is on. Now that I know where the SRS module is located (behind the passenger kick panel), I think that I will check to see if it has power. Anyone want to take bets that I find yet another broken wire?

 

Oh, I forgot to thank everyone for the help on diagnosing and replacing my ignition switch. Just a few weeks ago I was driving home when I noticed that she really didn't like starting for a dead stop. That is also when I noticed that the check engine light came on.


Got home and pulled the codes and there were four of them, all related to the transmission. I was thinking that this was going to be expensive, but a search revealed that power to several of the transmission sensors goes through the ignition switch.


Got one on eBay, watched a couple videos on the old youtube, and had the switch swapped out in about two hours.


Without this site, I don't know how much I would have spent fixing those codes.


This site rocks! Everyone is so helpful. Not all car sites are this friendly and knowledgeable.

 

Good job sticking with it! Couple of things: When P1345 shows up, it means the distributor is off at least one tooth. Timing is not affected by rotating the distributor on this engine, and the PCM can not / does not, compensate for it, that's why it idled smooth. The pulse for ignition and injector timing originates at the crankshaft position sensor. The sensor does not move, and timing is not adjustable, it is fully controlled by the PCM. When the distributor is clocked correctly, (no P1345), adjusting camshaft retard aligns the camshaft position sensor, rotor segment, and the terminals in the cap, simultaneously. If the distributor is off a tooth, or more, or camshaft retard is out of spec, the distance between the rotor segment and the terminals increases causing crossfire inside the cap. Just because P1345 is not present, doesn't necessarily mean camshaft retard is correct. It can be off as much as ~27 degrees before setting P1345. 360 degrees of distributor shaft rotation, and 13 teeth on the distributor gear, do the math If it's off by 27 degrees, there will be some serious crossfire going on inside the cap, and it might not set any DTC's! This is why camshaft retard must be checked/adjusted if the distributor is moved, removed, replaced, or disturbed. The adjustment is done by slightly rotating the distributor, and it's part of the job, just like setting the timing on older engines with a conventional distributor.