The weirdest thing happened to me on the way to work yesterday. My ABS light came on (it's been doing this a lot and at seemingly random times), and then the Brake! light came on (has only happened once or twice before). Then they randomly went out and a few second later came back on. Then my RPM's went from about 1500 to 3500 and I seemed to lose my transmission. The speedometer also dropped down to 0. I was able to limp it to work which was only about a mile away. I found out that I can select "2," and the car will shift into second gear, so I drove seven miles home in second gear. Putting the selector in D or over-D would cause the transmission to stay in first gear. When I started the car up to drive it home, I turned the air from defrost to vent; after that I couldn't get the blower fan to work, my windows wouldn't roll down, the console lights don't work, and who knows what else. On the way home, the Service Engine Soon light came on. The codes are 16 and 72. I don't know if this is related, but often when I turn off the engine, the tach stays stuck at around 750 RPMs. Any thoughts one what the problem could be?

I have a 1995 2door 4X4 Blazer with the 4.3 Vortec engine

 

No one has any ideas? Does anybody at least know what a code 72 is? That code is not listed in my Haynes manual.

 

Can somebody please give me input into this. I saw somewhere that a code 72 might have something to do with the speed sensor. How would I check this? Does anybody have information on how the speedometer/speed sensor etc. works on a '95 Blazer so I can try to narrow this down. It's weird that my windows, heater blower motor, and overhead lights stopped working as well, but all my fuses seem to be ok. Thanks for any help.

 

You VSS (vehicle speed sensor) is not communicating the output speed to the ECU properly. This has come up before on the forum and been discussed with better detail.

I would start by cleaning the VSS, but replacing it would work too. It isn't that expensive.

 

Thank you for the response. I will do more research on that. Is it just a coincidence that the windows, heater blower motor, and overhead lights stopped working at around the same time? Would the ABS and Brake light coming on have anything to do with this as well?

 

To be honest, I didn't read that far into your post. I was quite tired and had a migraine when I replied. Your post was a bit hard to read under the circumstances.

The ABS system uses the VSS too, so that makes sense. The rest of the stuff is likely caused by a failing ignition switch which is fairly common. Maybe take that route first before messing with the VSS.