Multi functional switch not working properly
 

Own a 2007 Grand Marquis with 50,000 miles.

Have three problems:

Number one, the multi functional switch that operates the windshield washer does not work properly. Installed a new multi functional switch and thought that would cure the problem. Only high speed wipers works. The problem began when the washer would come on while driving down the road, it would run dry and still be running. Unhooked the motor under the plastic tank that holds the water because it kept running and smelled like it would catch fire. Now all that works is wipers on high speed.

Second problem, there is a clunk under the car when slowing down and turning right or left. You can feel it in your feet through the floor boards.

Third problem, the AC only works through the vents under the windshield. Does not come through the dash.

Warranty has run out and do not have lots of money to have it fixed. Want to know what is wrong so when I do take it in can tell the dealer what is probably wrong. Otherwise has been my experience they run up a big bill and the problem is still not fixed. While still under warranty took it in for the clunk and they could not find the problem.

i have a older model grand marquis and the wipers wont work unless thier on high too... i think it might me a mercury thing idk....

the AC problem is a vacuum leak. check the vacuum lines behind the engine that feed back under the dash. There should be a check valve there and it may be blown out. If the lines are not connected, reconnect them and see if that sorts it. If not, replace that check valve.

It could also be the vent controller (though I'm not sure what it's called in newer cars - it's the blend door lever in mine, but then mine's an 88 model).

It could also be the vent actuator if it's not vacuum driven like the older cars. It could also be a single blown out actuator anywhere in the system. It would cause a big enough vacuum leak to prevent anything from working properly.

as for the wipers, I think there's a controller somewhere that takes care of the intermittent timing as well as low speed and washer control. That should be the cure for the problem and most likely a dealer part. On some older cars, the controller was built into the assembly with the wiper motor. That's not the case with yours though.

as for the clunk, check the control arm bushings on both sides. make sure that the rubber doesn't look squished anywhere around the bushings. it could also be ball joints. I'm certain it has something to do with the suspension. I've been trying to trace a rattle in my wife's 93 vic for a few years now (happens when you hit a bump but it's got new bushings all around the front end and almost everything has been replaced that's rubber up front as well as the shocks, so now I'm thinking about looking at body mounting bushings and frame bolt points on that car).

I wish you luck in finding the issues and hope that the fixes aren't much. Budget issues can kill a car with issues faster than driving badly sometimes.