Cant get my OBD2 scanner to work with the plug under the dash??

[car4685]

I have a '01 blazer. When I plug my scanner in it dosnt turn on? The way that it turns on is from power from the plug. I have a check engine light on. I have checked all the fuses that I can think it would be. Can you think of any other ones? It has a aftermarket cd player and alarm in it, both were in it when I bought it so I don't know anything about them. Someone told me that I had to put the stock radio back in, so I did, and that didnt work. This is the first time that I have tried to scan my truck, but I have scanned other cars so I know that it works. I would really like any help that I could get because my truck is running like crap and I need to know what to fix. Thanks for your help.....

[MT-2500]

Post deleted duplicate.

[MT-2500]

Check all fuses
You need battery power on pin 16 of diagnostic connector.
http://www.troublecodes.net/OBD2/

[car4685]

There should be hot power to the pin right? So I can just ground a test light and check it. What if these no power to it and the fuses are all good? thanks

[MT-2500]

Yes a test light or volt meter should show 12 volts to pin 16.

It should have battery voltage key on or off.
It is powered by fuse 3 cigar lighter in fuse block in end of dash.
Does cigar lighter have power to it or does it work

Check fuse for power on both sides.
Orange wire from it feeds cigar lighter and pin 16 is hooked into the cigar lighter orange wire for 12 volt power.

If you can not find where it is losing voltage you can jumper a fused jumper into pin 16 and get scanner to operate.
But if the fuse blows you will need to find short.
Shorts are usually in the cigar lighter socket ot lighter itself.
Sometimes kids stick coins in them to.
Or cut the wire in back of pin 16 to bypass short.
Good Luck

[mike2004tct]

I'm not so sure about power always at pin 16.

My scanner won't come on unless my key is in the "On" position.


Now I said, I'm not sure about that.
Is there another pin that enables the scanner, where 16 could have power, but one of the Bus pins is the actual 5V/12V supply to the scanner to enable it?

Guess I should google the OnBoard Data Bus structure.

(BTW, mine is an Actron Pocket Scan)

[MT-2500]

Pin 16 is scanner power pin.
Should be 12 volts key on or off.
http://www.troublecodes.net/OBD2/

Key may have to be on for scanner to kick in on data.

[mike2004tct]

Originally Posted by MT-2500

Pin 16 is scanner power pin.
Should be 12 volts key on or off.
http://www.troublecodes.net/OBD2/

Key may have to be on for scanner to kick in on data.

Yep, just checked mine.
Continuous power at 5 (gnd) to 16 (12V) key off.

Key needs to be on to collect data.

[ponchonutty]

There have been problems with the fuse panels on many GM vehicles where the BCM power from the pins you talk about isn't there. The fuse will show to be fine. I found this the hard way a few years ago when doing a remote starter for a GM dealship. Before I was done, I noticed the CEL was on but everything started and acted fine otherwise. Tried to hook up their Tech2 but it wouldn't power up. Ended up being an internal short inside the fuse block. This was on an Express van.

[car4685]

Thanks for all of your help guys...I found that the cig. fuse was blown and replaced and the scanner worked. I got some codes and posted them on is site in a new thread so if you could help me with that , that would be great. thanks