I have installed a 4 post relay on my 280SE automatic for the throttle switch. With this relay, the throttle switch does not handle the full amperage load of the large 3 position solenoid. Instead the throttle switch simply energizes the relay coil and then the relay sends the juice to the trans solenoid.
The issue I had prior was that the points on the throttle switch would get “dirty” after a couple of years of use. My theory was the amps from the solenoid caused the points to arc over and over again as the throttle opened and closed during normal driving. So far, the relay has worked very well for the last 7 or so years.
Last month, I went to a car show and got into a traffic jam getting into the parking lot. It was really hot as it often is is Dallas.The car sat and idled in gear for 15 minutes or so with very little movement. Long story short, the relay coil stoppped working and the trans would not go into low pressure mode. Upon inspection, I noticed the two posts for the coil were loose enough to twist. My thinking is the coil got hot and the posts got loose in the plastic base. And therefore explaining the erratic action from the coil.
So my question is how long can a relay coil be energized before it gets too hot? Is it possible that can happen? Normally I do not idle for long periods of time and last month was the first.
Any thoughts?
