Electrical problem V8 Four Wheel Drive Automatic 140K miles
I need some in depth technical help please - here's the long sad story in 3 part harmony: Recently this Yukon (5.7L Auto Trans) would start fine in the morning, drive fine to work, start up fine after work, but shutting it off 1/2 hour later and trying to restart again would get no action from the starter at all. Let it sit and hour and then it started up fine. Happened again the next day only this time it took 2-3 hours before it would restart. I thought the starter was the culprit, so spent big bucks on a new starter and put it in.
It started up just fine but the next time it was driven for a while and shut
off for about 30 minutes, it would not restart again. Not even after waiting
more than 12 hours. Here are the results of some testing that I have done:
No check engine lite was ever present, and plugging in my OBD2 reader showed no error codes. Security light seems to function normally - stays on for about 5 seconds after turning on the key and then goes off.
The fuel pump does run when the key is turned on.
The fuses are good.
The starter relay is good. Jumped across the output terminals of the starter relay socket and the starter cranks fine, motor starts but will run for just a couple of seconds.
The ignition switch on this vehicle was just replaced about a year ago.
According to the factory manual that I have, there is supposed to be a ground present on one side of the starter relay (coil side) this is pin 85 on the relay, and then when the ignition key is turned to start, there should be +12 volts on the other side of that relay coil which is pin 86. I dont see either when I put my meter on there. The diagnostics dont appear to take into account the theft deterrent system, which I suspect may be the reason. Should I be able to see theft deterrent trouble codes with the OBD2 reader as well? I tried adding a ground to pin 85 of the starter relay but it still wont start. What else can I do to figure out what is keeping the starter relay from working? Is there a way to bypass the theft deterrent system? HELP ! I'm stuck.
Thanks in advance.
have the same problem?
Sunday, May 4th, 2008 AT 8:09 PM