This should be easy to find, as you are losing power somewhere.
FIRST thing to do is remove both battery terminal clamps and CLEAN them. Buy a good "battery brush" if you don't have one, like this:
Yep - both brand new and clean. That's one I keep up on
If that does not clear the problem, then find out WHERE you are losing power
Get your test lamp "rigged" with clip leads so you can see it while reaching in to turn the key to "crank."
Also see if turning headlights on/ off affects problem
No effect
Start by clipping test lamp to engine block, and starter relay battery stud
Does it stay lit when problem appears?
Then problem is further downstream
If it goes out, it's right there somewhere, battery, cables, clamps. Cables can fail internally with corrosion!!
Doesn't go out but dims some - Normal?
If you got a light but no crank in the first test, move further on
Backprobe the bulkhead connector where the fuse link enters, with lamp grounded to block. If it lights / no crank, problem is elsewhere.
Probe the push one yellow wire at the starter relay. No/ dimming light at that point means it's between the bulkhead (in test above) and the starter relay.
Found it - Screw loose on this connector. Cleaned and snugged. I'll run it for a while and see how it goes.
Again, thanks for your help on this!
