I have a 88 chevy Cheyenne k1500 4.3L and it doesnt have 12 volts at dlc it is instead 1.8 volts. My scan tool blinks quickly but wont start up. Just looking for ideas on my problem and how to tackle so thanks to helpers. I checked all fuses they were all good except crk which is a 5 amp fuse labeled crank in the wiring diagram

 

My truck has no cigarette lighter but it does have a ecm and ignition fuse and they are both not blown. It will crank over and has spark and fuel just doesn't start and the scan tool wont light up.

 

Do you have the correct module in your scan tool? OBD1 had several plug in modules per different vehicle, that's about all I remember of them.

 

so I have a obd 1 adapter to fit my obd 2 scanner and it is supposed to be correct and seems to fit correct. I have 12v at all fuses including ecm fuse but 1.8v at the dlc port. The scanner will blink on for a fraction of a second to try to light up. The truck rolls fine with spark and fuel pump prime but no start still and as far as I understand it needs 12v to run scanner and ecm.

 

I did find a bee's nest behind obd1 port but I believe my problem could be at the junction box under hood on passenger side. Does it matter which wires go where on the junction box under hood

 

I have looked at the wiring diagrams so many times and followed so many videos that promise to fix the truck just wont run or scan or give anything but 1.8v at the obd 1 port.

 

The 3 orange wires are connected and then a 4th wire to them that goes to that junction block but it seems odd. Maybe I need to go to a junk yard to take pictures cuz the wiring diagrams aren't helpful