Summer will not crank, no click WINTER always starts

    Lets try you that deal exclusively with Caddys

    Live in Minnesota

    In the SUMMER even a short drive where it doesn't get up to full operating temperature or even full up to it. I can get out to fuel up let's say. After this 15 minute shut down down....no start, no crank, no click even. Dashboard lights come on normally. Waiting, 15-20 minutes or so, zoom starts and everything works fine. I have started opening the hood while shopping in the hope it cools down faster. Reason below.

    In the WINTER, like right now I NEVER have the problem. Never.

New battery
Cables clean tight

    Garage wants to replace the starter....no I don't think so.
    What relay or ignition module could get so warm to intermittently fail when WARM but in COLD weather never is affected?

    I can't keep letting it run with doors locked in Summer to dodge the problem. So, guys, PLEASE help point me in the right direction. Battery and connections are fine.

    I can find nobody else with this issue, (Except accidentally in Caddy Catera forum..never found answer) so before I take it in and run up a big diagnostic bill, maybe someone here may help. Thanks in advance.