Dead Electrical

[IH8MUDTOO]

Been driving the 6.2 Suburban for a while and its been a pleasure. Had a starting issue this week that has me scratching my head.

Cranked to start one morning and didn't fire on the first crank, which is typical. Allowed GP to cycle again, and when light went off, I cranked again and got a fuse/breaker "pop" sound, and everything went out--no dash lights, no dome light, and no key-in-ignition buzz.

One battery is new (bought in September) and the other was tested at the auto parts store, in September, as "good".

I checked fuses under the dash, all are intact. I assume Circuit breakers would re-set after disconnecting both batteries, which I did, but still no power.

Search on this site indicates nothing specific (found some interesting Ford 6.9 stuff). Any suggestions?

I think my next step should be to unravel the wire loom and inspect the fusible link (blue) wire to the solenoid at the firewall.

 

[towcat]

do the headlights work?

 

[IH8MUDTOO]

no, nothing electrical works.

An early thought was that possibly the older battery died and shorted the newer (post by "doc" 25 JAN 2007). But I think my problem is in wires/fuse/circuit breaker.

I don't have a digital meter, but have a test light. each battery (tested separate) has voltage to illuminate the test light.
I know voltage doesn't start the motor, but I would at least have a dome light and possibly dash lights and marker lights.

 

[towcat]

at minimum, if the head lights work and nothing else does, the fusible linke of the firewall is the culprit. since nothing works, start following wires from the battery to the junction block on the firewall but also do check if you still have any fusible links down by the starter.

 

[IH8MUDTOO]

Well I figured it out.

Followed the wires as Towcat suggested, and found several down by the starter. None appeared to be burned. I then followed the wires to the solenoid on the firewall, and none appeared to be burned.

Figuring I had nothing to lose (and since I don't have a meter to test the battery amperage) I hooked up the jumper cables from another vehicle. Viola, I had power in the cab of the Suburban. Not sufficient to turn the starter, but all accessories (lights, windows, etc.) worked.

I left the jumper cables on for about five minutes, and cranked the Suburban. It started on the second attempt (this is normal).

So back to "Doc's" post in the 6.9 IDI thread--appears one battery (though it tested good in September) sapped the other (the new one bought in September).

Can you think of any other explanation?

 

[Goofyexponent]

Bad battery cable perhaps? Or a bad ground from the batteries?

 

[opusd2]

Dead short somewhere, constant drain into a failing solenoid or alternator are other causes. Oh, and make sure you have good battery cables