Hot weather no crank/no start
 

Hi. I have a 2013 Elantra GLS that has recently started having an intermittent, weather-related no-start issue. When the passenger compartment of the car is warm from sitting in the sun, the car will not crank. When I turn the ignition switch, there is a single click audible under the hood (though not from inside the car). When the engine compartment is warm but the passenger compartment is cool, it’s not a problem. From calling roadside service and googling the problem, here’s that we’ve tried so far:

• check that battery is good.
• swap out starter fuse and starter relay
• run through the gears, try to start in park and neutral

I’ve taken it to the dealership twice and he wasn’t able to replicate the problem because it was a cloudy day. His opinion is that intermittent no-start is usually starter and suggested we replace it, quoting me $525, but telling me he couldn’t guarantee that’s what it is. My regular mechanic also wants to start with the starter. I’m hesitant to spend the money without trying to diagnosis it a little better.

We finally had some sunshine to cause the problem and my partner tried replacing the unkeyed side of ignition switch, because it was cheap and easy. Nothing. Then he pulled the starter relay and bypassed it and my car started. We tried several more times to confirm that with the relay in, the car doesn’t start. Bypassing the relay, the car does start. That seems to suggest to me (who knows next to nothing about cars) that the relay is bad, yet we’ve swapped out the relay for two others and none of them work. We have not tried a brand new relay.

Does this mean it’s definitely not the starter? I’ve read that this means it’s somewhere on the ignition circuit. (I believe I interpreted that correctly!) What should my next step be? I’m torn between just taking it back to my mechanic to have him diagnose it or replacing the keyed side of the ignition switch ourselves to rule that out first. I don’t mind paying my mechanic; I’m just trying to make the best use of my time and money and don’t want to diagnose by replacing expensive parts. In the meantime, I’m driving my Dodge Dakota, which is costing me a fortune with gas prices being what they are. At the rate we’re going, I’m going to spend more in gas than what I would pay my mechanic!

Thanks for any and all suggestions.