Hot Weather Ignition Problem

I have a 1988, Ford F-250, 7.3 Diesel, 4X4.

For the past few years, on a hot day, if I have started and stopped a few times and turned off the engine it does not want to restart. The ignition switch has been replaced twice. It works great for a couple of weeks and then reverts. Yesterday,for the 1st time it would not engage at all. However, if I turned off the switch all the way back to AUX I turned on and off the radio it kicked right over. Seems there must be something not making elec. contact, but oly during a hot day. Where do I look for a fix?



Thanks

I would start with the battery. Have it checked on a hot day at an autopart’s store. They often will check the battery for free. Do it on a hot day with the engine fully warmed up.

Also check the battery cables. All ends of all cables. Not just the ends that attach to the battery.

There’s a starter relay located under the hood at the right front fender. It could be this relay is getting hot and failing to supply voltage to the starter solenoid.

Tester