98 Suburban OBDII Connector Dead

[nailerdog]

I have a friend with a 98 Sub with a Service engine Light on. When I connected my reader It didn't power-up. It normally powers up as soon as you connect it with the ignition on or off but won't read codes until you turn the ignition on. Any ideas where to look for the problem? I tested the tool on another truck and it's working fine.


Thanks

[praisethelowered]

Have you checked your fuses? I believe there is one for the ecm.

[2000CAYukon]

Pin 16 is +12 volts. Pin 5 is ground. Use a test light or VOM to see which pin is bad. Could be something as simple as a bad ground wire.

//2000CAYukon

[nailerdog]

Checked all fuses and they are OK. Can't seem to find a wiring or ground issue. The ground is OK and on the correct pin. I only read about 6 volts on pin 16.

Where does the power for the diagnostic plug come from?

One other thing, the courtesy lamp fuse blows instantly when replaced. I'm thinking it's the headlight switch assembly. Can't imagine any connection to this isue?

[maxwedge]

The ctsy fuse feeds the power at the obd 11 connector so that is that problem, now find the short in ctsy lites, look in the cigar liters for foreign objects.