2002 blazer
When starting it will not disengage when the key is turned to run. Brand new ignition switch. No voltage going through the crank wire on the ignition switch harness UNTIL the key is set to start. Then, when I put the key into run I still have voltage until I turn the car off. Lol what's going on? Plz help

 

 

When you turn back to run after start and "I stiil have voltage until I turn the car off", where do you measure this voltage? I assume that if the starter stays energized after the truck starts that its pretty violent but if you have a helper pull the crank fuse at the moment you return to run and see if the starter disengages.

George

 

Yes I hop out and pull the starter relay, then the starter disengages. First I measured the ppl/wht wire at terminal 85 of the starter relay feed. Then I measured the yellow wire coming out of the ignition switch and have voltage at both these points. I lost voltage to the yellow wire when I pulled the crank fuse but had to run to town before further investigation

 

The two most likely causes are:

1. A start relay thats sticking (try tapping it right before you pull it). You can also swap with a known good relay.
2. A faulty ignition switch that does not let the start voltage go when returning to run. Leave the relay in place, start the truck and pull the crank fuse. Assuming the starter lets go, then measure the voltage coming into the crank fuse at the fuse socket. If pulling the crank fuse does not release the starter then pull the relay.

Every repair is still suspect until the repair is verified even if a new replacement part was used. In the case of electrical part replacement anything other than AC Delco can end up causing a new problem which is why the parts cannon can cause us to chase our tails. Parts should only be replaced after diagnosis confirms that the part in question is faulty.

George

 

Im finding that I have voltage going into the starter relay even with the crank fuse pulled. Wouldn't that rule out the ignition switch and the relay? I've swapped that relay out with the other 2 in that fuse box to no avail. Same situation with both the new ignition switch and old ignition switch

 

Let me make sure that I understand this:

1. At key on there is no starter engagement
2. When you move the ignition switch to start you get normal starter engagement but when you return the ignition switch to run the starter stays engaged and only stops when you turn the ignition switch off
3. When this happens after you have returned the ignition to run the starter quits when you pull the relay but if you leave the relay in and pull the crank fuse, the starter stays engaged?

One relay socket has always on 12v


George

 

Correct!

 

Create the fault, pull the crank fuse and verify that the starter is still engaged, pull the relay to kill the starter, leave the ignition switch in run and then measure the dc voltage in every relay socket, meter black lead to battery negative terminal and report the values.

George

 

85 = 13.5v
86 = -0.01v
87 = -0.01v
30 = 14v