Intermittent no start?

KRISTA STARK

MEMBER
1997 GMC SIERRA
5.7L
V8
4WD
AUTOMATIC
360,100 MILES

The vehicle will normally start right up fine for about a week or so and then won't start at all. Changed all the battery terminals and the way they are connected. This has been going on for about a month now. All connections are tight and proper. Underneath where the starter is, all is tight and proper. The wires all appear to be good. The starter is about a year old as is the battery. We replaced both at the same time. Any suggestions?

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

If the starter isn't engaging, the first thing I would check is the relay. The issue is this. Since it is intermittent, it may test good even if it is the cause. Have you done anything with the starter relay?

Also, it could be related to the park/neutral switch. When it happens, see if it starts in neutral.

One other thought. When this happens, have a helper turn the key to the start position while you check for power at the purple wire on the starter motor. The wire should only get 12v when the key is in the start position. If there is power, the new starter has an intermittent issue.

Let me know when this happens if you hear a click from the starter motor.

Here is a link you may find helpful:

https://www.2carpros.com/articles/starter-not-working-repair

I attached the starter circuit wiring schematic below, so you have a reference.

Let me know what you find.

Joe

See pics below.

Images (Click to make bigger)