1996 s10 zr2 wiring problem

[behead]

Im having problems with my zr2. first off its a 96 s10 zr2 4x4 4.3 5 speed. when i took it to get inspected today, the scanner wouldnt recognize the 'dlc'. does the dlc have a fuse? the check engine light isnt on. the bulb is working. also, my brake light quit, so i traced it to the wire coming from hot to the fuse. im assuming i can run a new wire from the fuse directly to the battery. or does this need to come from a different source? any links to the dlc scematics would be helpful. i know the engine was replaced about a year ago. im hoping they didnt mess the wiring up. the truck runs great and doesnt seem to have anything not workng. thanks for any advice

[MT-2500]

Originally Posted by behead

Im having problems with my zr2. first off its a 96 s10 zr2 4x4 4.3 5 speed. when i took it to get inspected today, the scanner wouldnt recognize the 'dlc'. does the dlc have a fuse? the check engine light isnt on. the bulb is working. also, my brake light quit, so i traced it to the wire coming from hot to the fuse. im assuming i can run a new wire from the fuse directly to the battery. or does this need to come from a different source? any links to the dlc scematics would be helpful. i know the engine was replaced about a year ago. im hoping they didnt mess the wiring up. the truck runs great and doesnt seem to have anything not workng. thanks for any advice

http://www.troublecodes.net/OBD2/

Pin 16 should have battery power all time if so check the ground wire for good ground.
No 12 volts on pin 16.
Usually caused by a fuse blowed.
May be the cigar lighter fuse.
But always best to check all fuses for 12 volt power on both side when you have a power supply problem.

[MT-2500]

On yours it is the PWR AUX fuse no. 7 a 25 amp fuse in I/P panel fuse box.
Let us know how it goes.

[behead]

hey, thanks for the help. when i hook my mulimeter to the ground and power plug pins i get .1 volts. when i pull out the ground and put it to the frame, im pulling about 11.5 volts. im assuming my ground in the plug is bad. should i go through the pain of tracing that wire to the bad connection? or can i just run another wire to ground and cut the old 1? thanks for the help.

[eric_454]

Just my $0.02 worth, but I left a ground loose on the back of a 4.3 head once after an engine change (hard to get a wrench on) and had all kinds of electrical gremlins surface a little at a time. Might check the ecm grounds on the back of each head and the body ground strap from passenger head to the firewall. That and look at the pass-through on the firewall for your dead power wire. Notorious around here anyway.

Look here for 97 wiring and ground I'm told it's the same.
http://www.autolib.diakom.ru/CAR/Che...NG%20DIAGRAMS/
Look here in particular.
http://www.autolib.diakom.ru/CAR/Che...GRAMS/9317.pdf

[MT-2500]

Originally Posted by behead

hey, thanks for the help. when i hook my mulimeter to the ground and power plug pins i get .1 volts. when i pull out the ground and put it to the frame, im pulling about 11.5 volts. im assuming my ground in the plug is bad. should i go through the pain of tracing that wire to the bad connection? or can i just run another wire to ground and cut the old 1? thanks for the help.

If everything else is working ok yes just tie in a ground wire to that ground but leave the ground wire at plugin as is.
Do not cut the wire there just tie in a extra ground.
But as Eric said you may have a bad ground some place on body or head.
If you are just getting .1 volt or very low volts you have a bad ground someplace where other stuff may be grounded.
Good Luck and let us know how it goes.

[behead]

hmm.I guess i jumped the gun a bit. the manual i have says pin 1 is ground. but according to this: http://www.troublecodes.net/OBD2/ pin 1 is free and pin 4 is chassis ground, pin 5 is signal ground. Im headed to check them now. should i be getting any kind of current in the signal ground pin? Also I dont think I have any other electrical problems, other than a dead wire coming from the battery to the fuse box for the brakes lights. I ran anew hot and they work fine now. I beleieve the lights are grounded in the back anyways. Ill let u guys know.

[behead]

now I am really confused. Both pins have current. The plug has power. Seeing as
I dont have a scanner tool handy, is there a way to test each pin for some kinda current? Im hoping the shop didnt screw me. I have to take it back to them to get it reinspected.

[MT-2500]

Originally Posted by behead

now I am really confused. Both pins have current. The plug has power. Seeing as
I dont have a scanner tool handy, is there a way to test each pin for some kinda current? Im hoping the shop didnt screw me. I have to take it back to them to get it reinspected.

A volt/ohm meter or old bulb type test light will check for voltage.
Just do not us a bulb test light for computer circuits.

For checking for good ground I reverse a test light tp positive 12 volt feed and touch the ground.
If test light lights up good and strong you have a good ground.

On OBD 11 plug pin 4 is body /battery ground.
Do not fool around with the signal ground as it may run threw the VCM/PCM computer.

[behead]

I have good ground in the pin 4 and 5. its reading around 12v. Do you mean pin 1 on odb is ground? or pin 11? pin 1 has no ground. I can check 11. As far as negative and positive being at the plug, all is well. Would any of the other pins cause the scanner to read "cannot recognize dlc"?

oops got u obd2 pin 4.

[MT-2500]

Originally Posted by behead

I have good ground in the pin 4 and 5. its reading around 12v. Do you mean pin 1 on odb is ground? or pin 11? pin 1 has no ground. I can check 11. As far as negative and positive being at the plug, all is well. Would any of the other pins cause the scanner to read "cannot recognize dlc"?

oops got u obd2 pin 4.

Pin 4 is ground and pin 16 is 12 volt power feed.

If ground and power scanner should power up.
If not try another scanner.

If scanner powers up but does not read out check pligin and wires from plugin to computer.

Does check engine light come on key on?

[behead]

yes the check engine light comes on with the key on acc. Its not on with the key on "run". Im going to take it somewhere just to see if the scanner hooks up. I have to take it to the same shop to get reinspected, so I am hoping their scan tool isnt broken. I wouldnt think it is tho.

All the connections to the computer look good.

[MT-2500]

Originally Posted by behead

yes the check engine light comes on with the key on acc. Its not on with the key on "run". Im going to take it somewhere just to see if the scanner hooks up. I have to take it to the same shop to get reinspected, so I am hoping their scan tool isnt broken. I wouldnt think it is tho.

All the connections to the computer look good.

It should come on key on engine off.
You may have a defective VCM/pcm computer.

But scanner should still power up if good power and ground to it.

Check it with ando ther known good scanner first.
or even try you sanner on anothe vechical.

Good Luck and let us know how it goes.

Also unplug a sensor or two and see if it sets check engine light.
If computer and check engine light working right unpluging sensor should set code and turn on check engine light engine running.

The last time I had one the that the check engine light did not come on key on engine off it was a bad VCM/PCM computer.
But you could have a different problem.
Only a lot of proper testing will tell.

Let us know how it goes.