Heat related ignition switch problem ?

[mog]

A month ago when I traveled to a hot (90-100°F or 32-37°C) area and again this weekend (100°F or 37°C) I had the following problem.
When trying to start in the hot weather everything works ‘as normal’ until I go from ignition on to start and then no ‘ignition position power’ but the starter turns over as normal.
So as I am turning the switch from ‘ignition on’ to ‘start’ all the normal warning lights that are ‘on’ in the instrument panel go ‘out’ but the starter turns.
In troubleshooting I pulled the plastic cover off the steering column and when this no power situation happens, if I rap on the end of the ignition switch were the wiring are attached (opposite the key) with the handle of a screwdriver it will start.
Now of course the simple (well relatively) solution is to replace the ignition switch. But between the issue of the ignition and doors getting keyed alike again and having to drill out the shear-head bolt, I though I’d ask if someone else has had this problem.
Is there perhaps some dielectric grease normally in the ignition switch that could be melting at this higher temperature and causing a problem? Or something else ‘heat related’ in the switch ?
When I’m back in <80°F (<26°C) temperature the ignition switch works as normal, no problems.
Any thoughts or should I just order a new switch and rekey the doors ?
-
(2002 Fuso FG, manual, 61,000 miles)

 

[kerry]

Never had any heat related issues with my ignition switch and the truck has 200k+ miles. Does everything work o nthe dash once the engine starts or are you still without power to the dash after it starts? I'd try spraying some electrical cleaner into the contacts before replacing the switch.

 

[mog]

Never had any heat related issues with my ignition switch and the truck has 200k+ miles. Does everything work on the dash once the engine starts or are you still without power to the dash after it starts? I'd try spraying some electrical cleaner into the contacts before replacing the switch.

Once the super hi-tech protocol of whacking the ignition switch body with the screwdriver handle (it only takes a couple whacks) everything (instrument lights, etc) work as normal.
I've had solenoids act 'weird' in the heat (not on the Fuso), but the switch sure seems to be a simple device to be affected by that.
I was thinking it was something else in the circuit, but the direct action (whacking) is an instance 'fix', so I'd say 99% sure it is the switch.
I've spray with contact cleaner, but I'm back in cool weather. Maybe I'll try a controlled test with a heat gun raising the temp in the ignition switch area ?

 

[Buckstopper]

That is too funny. You gave me a flashback to my childhood. My dad drove a 1964 VW van and he used to have me crawl under the engine with a screwdriver and he would tell me to whack that silver thing when I heard it click. Worked every time.

Wish I still had that van.

Buckstopper