when i turn the air on it works great for about a half hour than it seems to go to heat the cental vents turn off and the floor vents start to go to hot air if i stop the car and than start it again in 5 min it goes back to air con again can any one tell what is happen i have a 1989 xjs v12 conv

Submitted by stevejag@sbcgl… on Tue, 07/05/2011 - 17:22

Bob,

One thing to check for your A/C going warm is the ground connection at the lower edge of the A/C control module. It's a spade connection that sometimes gets tarnished and causes a high resistance. Clean it up and make sure the circuit from it to ground has a very low resistance. In some instances I have run a new ground just to make sure that's covered.

Good luck!

Submitted by browder@nuventrs.com on Tue, 07/05/2011 - 11:22

Haven't experienced this with my '90 XJS conv, but have noticed that only my center dash vent blows cold air...nothing out of the side dash vents or any floor ones ( which I have no idea where they are ). Still learning this beast ;-)