I had the same problem on my 86 cutlass. I used a ford solenoid from a late 80's crown vic. I've attached a picture on how to wire it. But instead of using a piece of wire as the short I used a piece of copper pipe for plumbing. I cleaned it very well then flattened it with a hammer. You have to bend a kink in it, you should be able to see what I mean by looking at the solenoid. Then all you have to do is drill a couple of holes and mount and wire it. I never had a problem after that even on hot summer days. There are kits out there but I say DIY. Hope it helps.