M1009 starting question

[n8roro]

This morning I tried to start and got nothing. The lights worked, but there was no sound at all when I turned the key. No starter and no clicking. Would that be a loose wire somewhere or a bad starter relay?

Later in the day when it was warm it started right up. That made me wonder if it is the ignition switch.

I'm confused about what to look into first, so any help is appreciated.

 

[98G]

Test both batteries and their connections

 

[Bighorn]

If you have a voltmeter or can get one, that would be helpful.

What you have is a key switch that provides power to a small relay behind the dash panel which controls power to the starter solenoid which controls power to the starter windings.

Next time you try to start the truck;
Locate the starter relay under the dash on a plate behind where a stereo would go if it were a civilian Blazer.
Test for voltage at the smaller terminals when you turn the key.
If no power at the smaller terminals, then there is a problem with the key switch or power in that circuit.
If power at the smaller terminals when turning the key, then check the larger terminals of the relay for power (no click pretty much tells you it is not engaging but test it anyways).
If the key switch is providing power, and the under dash relay is engaging and sending power to the solenoid on the starter but still no starter engagement; test for power at the starter solenoid.
It may help to have a friend work the key switch while you handle the test leads.

 

[Bighorn]

Test both batteries and their connections

Yeah, do this first ^^^
I had this happen a couple of times on various equipment.
The battery terminals can be loose or corrosion present between connector and terminal that allows the lights on the dash to work normally until you turn the key to start and the current load causes everything to go dead.

 

[n8roro]

Thanks for your help. The breakdown of the sequence of events when turning the key is very helpful. The battery voltage is good and the relay I replaced a week or so ago. I'll check the relay if it happens again. I'll remove and reinstall the battery connections with some dielectric grease to eliminate that possibility. I suppose going over all the connections in the junction bars in the same way couldn't hurt.

 

[madaro]

what ended up happening ? did you clean it up and alls well ?

 

[n8roro]

All is well. I replaced the relay, but when I took out the stock one I noticed one wire was loose causing the intermittent starting problem. Temperature was not a factor in the end.