2005 Hummer H2. Started off with noticing that the tach was fluctuating even though engine speed was steady and A/C stopped cooling. Pulled over to check it out and the blinkers weren't working. Shut engine off and went to restart it, but it would not do anything. The starter never tries to turn. The gauges all work but nothing happens.Battery is good. I finally just turned key on and touched a screw driver to starter positive and the solenoid and the engine cranked right up. Tach still fluctuating and A/C not working and blinkers still not working. I checked for codes and had a code P0165. Any ideas????

 

Possible causes
- Faulty Heated Oxygen Sensor Bank 2 Sensor 3
- Heated Oxygen Sensor Bank 2 Sensor 3 harness is open or shorted
- Heated Oxygen Sensor Bank 2 Sensor 3 circuit poor electrical connection

Read more: P0165 O2 Sensor Circuit Slow Response Bank 2 Sensor 3 OBDII Engine Light Trouble Code | Engine-Codes.com

 

Sorry the code i had was from a previous failure that I did not clear. There are no codes and no check engine lights. I just drove it for about an hour and no codes. I can crank it up with the screw driver at the starter and it drives great other than a/c not working properly and blinkers not working. Just replaced the ignition switch and it did not help.

 

Figured it out. It was a small 10 amp fuse that was burnt in the box under the hood. There are several fuses that have something to do with the ignition and this was one of them.

 

Amazing how a little fuse can cause so much trouble.
I bet it feels good that the problem required a simple fix.