I have a 91 745t with two non- functioning brake lights. Fuse is OK and so are the bulbs. Any ideas? The other problem is when the car warms up it idles too high. When cold it idles fine at 850 or so but as soon as the temp guage hits operating temp (half way or so), it begins to idle at 1300 or so. Throttle body has been cleaned and idle set at a Volvo shop. Vacuum lines have been checked and changed. Did I miss one? Any ideas? Thanks in advance.

Mac
1991 745SE

The brake light outage might be caused by the brake light switch or by the bulb failure warning relay. I usually test these by substituting the relay with a known good one. I have heard of others on the board resoldering the relay with good results too.

The idle problem might be caused by a dirty idle air motor. It is the silver cylinder mounted under the intake manifold and has 2 large hoses attached to it. Remove the hoses and the one electrical connection to it and remove it from its mount. Clean it out with carburetor cleaner and reinstall. I am assuming that the Volvo dealer made sure the throttle switch was adjusted when the throttle valve was cleaned and idle speed set?

John

The IAC valve was pulled and I did exactly that with it- cleaned it with carb cleaner. It was moving free when I put it back in. As for the TPS I think that if it wasn't adjusted properly the idle would be wrong hot or cold. Am I wrong?

Mac
1991 745SE