Hey guys I have inherited a blazer that is possessed. Ready here we go. First problem the truck had was the A/C stopped working then the fan for the vent stopped, then the windows stopped, then the abs light came on and no more abs, then the gas mileage started dropping dramatically, then the truck started shifting erratically holding way to long in first, then the truck started to over heat if you drive 45-50 it hangs a little above normal but go any faster and it pins at the top and boils the antifreeze. Now I briefly looked at the window problem, So I tested the wires at the motor and got nothing so I pulled the fuse box and tested the wires going into the window fuse and got nothing. Now some history I got from the Ex owner. These problems didn't come at once they were spread out over an 8 month period with a week or so space in between problems. Second is that he did drive this thing into a ditch and hit the guard rail hard enough to bend the tow hook. Airbags DID NOT deploy. Now my first assumption is that the computer is bad and I would have changed it but a tech at the dealer had told me to check the body control module. I am not familiar with this so I figured come on here and ask first since I have been successfully helped before. Any help would be awesome the truck is in pretty good shape other then this problem. Thanks
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looks like no one answered you. i have no clue. but it does sound like the computer. all that you and i know is its electrical. my moms van did some stuff like that when here alternater was going out and burnt out the driver side power window and she had to have the computer replaced because of that also

 

check engine light on? have you tried getting any codes read.

 

Ya four codes come up. 1. P0147 Bank 1 sensor 3 Heater circuit 2. P0420 Catalystefficiency below threshold bank 1 And # 3 & 4 are the same P0719 Brake switch B circuit low input. Ya noom14921992 it doesn’t seem like to many people want to tackle this one. I don’t blame them that’s how I feel. Its about to go in the bargain news if it goes beyond a computer.


Sorry it took so long to respond but it wouldnt let me post a repley on here it was very frustrating any help will be great cause im planning on buying the computer early next week but if its not that then im f**ked cause i have to give mine for a core and its like $120

 

The computer has nothing to do with the windows or the fan... I would really look into the grounds. Find, disconnect, clean, and reconnect all grounds in the engine compartment.

 

wouldn't the pcm control the power that is distributed to the fuse block? could the grounds really just start to fail in order like this? I could understand some of it being grounds but what about the brakes and tranny stuff? this thing is just crazy my brother is the one who gave it to me so i saw everything happen to it and I have never seen anything like it.

 

No, that is done at the ignition switch. Which I suppose could also be a possibility.

Grounds can cause all kinds of screwy things to happen. A faulty ground to the PCM can cause some things to not work one day and other things to not work the next. It is finicky.

And please do not criticize us for not responding. Many people were having the same exact problem that you were experiencing with difficulty posting. No need to state how many views your thread has gotten without responses. For one thing, its responses and comments like that which will quite often cause people who would regularly respond to just hit the back button and move along.

 

I actually just put that there today cause i came on and saw like 2 weeks of new posts and no love over here it wasn't meant in a spiteful way I would definitely save that for after i got help just for that reason lol j/k. it was more of a response to noom14921992. I removed it so not to offend anyone. sorry. Is there a main ground for the pcm i should check? I went in and checked some of the wires and they seem ok. this is my first suv/truck I'm used to working on cars but this is mythird Chevy and ill tell you they defiantly have messed up electrical problems. one of which was a Chevy Corsica and i most have changed the coil and computer like 3 or 4 time in a couple years. have you ever heard of a body control module i think they meant the pcm. cause i cant find any info on the body control module in my Haynes book.

 

There is no body control module on these trucks.

About electrical problems, some are worse than others. It seems to depend on the luck of the draw.

I have seen corrosion on the plugs at the back of the underhood fuse box. But you haven't told us what you are working with yet either... From the codes, I can tell that it is a 96 or newer with a slight possibility that it is a 95.

As far as ground locations, again, I really need to know what you are working on to tell you further. There are some on the radiator core support. Some on the firewall. Just look for a bolt where a lot of black wires are pinned to the sheetmetal. Remove and clean off each individual ring terminal if you can, then clean the metal with some emery cloth, and finally slather some dielectric grease between any metal to metal contact to protect the connection and bolt it back on.

Electrical problems are the very most difficult thing to diagnose.

 

Im sorry I thought i wrote in the first message its a 97 4x4 blazer