Back up sensors/ball joint

[Whodat]

When I put my Expedition in reverse it says check back up system and I have noticed the back up sensors do not work. Has anyone had this problem? Also I hear a clunking noise in the front driverside area under the gas pedal area, ball joint? Or worse? 161k

 

[joezek]

I have both same problems on mine. Mine's got 140K miles on it (2003 model). I noticed that if I move the right sensor wiring around then it will work for a few days. Also, it always works in the morning, but never works in the afternoon when it's hot outside. If it rains, it also always works... I'm thinking there's a connector with some minor corrosion in it.

The clunking on mine seems to be the lower shock rubber bushings. They're the only thing with any free play. I've jacked the truck several times and used pry bars to try and force the ball joints to move and they don't budge at all. I tried forcing the sway arm links and bushings around, and they're solid too.

Every thing is rock solid, but I can clunk the shock up and down about 1/8th inch and the only part of it that moves is the lower bushing...which is NOT replaceable. I'm planning on taking the lower bolt out and seeing about squeezing in some rubber filler material, or epoxy. Anything to fill up the free space inside the lower bushing.

You may have the same problem, or possibly a ball joint, sway bar bushing, control arm bushing, wheel bearing....

 

[Whodat]

Thanks for the info, I am going to get underneath it thus weekend and fix that clunking. As for the sensors, I guess o will follow the wiring, once I find it, and check every connection for corrosion.

Thanks again

 

[nvycrmn]

for the clunking, do as you guys are doing and check the shock mounts. that is where i had the problem. joe, you can replace the bushings in the shocks if you want to. just requires some lube and a c-clamp and some new bushing that you can pick up at the store for a few bucks. another thing to check for clunking is the driveshaft u-joints. could need replacing. as for the sensors, if it works when its raining, there is some corrosion somewhere and when the rain drop gets on that part, it completes the circuit. i had the problem with my 91 silverado and the speedo....