Pinging Noise??

[watyalokinat]

Help from all you experienced RV'ers. I have a 99 Discovery 37V. Cummins 275 HP with a freightliner chassis. I periodically have a pinging noise(sounds like a sonar ping) coming from under the dash when the MH is in gear and the parking brake is engaged or not engaged. This can happen when stationary or traveling down the highway. This does not happen when the MH is in neutral. It will get louder and softer at times and faster and slower at times, and most of the time it's not there at all. It may happen once or not at all during a trip. It may be there for a few minutes or for several hours of driving. There is no rhyme or reason when it happens or doesn't happen that I can determine. The unit runs great and all the gauges show fine and there are no warning lights coming on or off on the dash panel. I have eliminated that it is the warning for the jacks down or low on fluid. The noise to the best that I can determine is coming from a small black square box just under the dash up next to the steering column. This box has a place for a round plug to plug into, also a switch that is labeled idle inc/dec, and a switch that says engine/check. I happen to think it has to do with the parking brake?? I think the warning device is telling me something is wrong when in fact everything is ok?? But that's just my guess from someone inexperienced with all this stuff. So I'm turning to all of you for your wisdom and troubleshooting ideas. Have a great day!! Thanks Dave

[Skip426]

My 99 F/L chassis has a Park brake warning chime, that goes off when you shift the trans,into gear, without releasing the brake. What you discribe sounds like the switch controling the chime is sticking irraticly. If the chime is on for a long time it will slow down as it heats up. The same could be true for a seatbelt chime; my coach has the chime ; but it isn't wired up, to the belt clasp, so it never goes off. The chimes were easy to spot 1 1/2 " dia 1" deep two white wires and labled; seat belt / park brake, about a foot apart and hanging from the harness. The box,switches and round grey plug; with cap teathered to it are for a diagnostic hook up. Chimes should be close, but because the harness is subject to being routed any which way by the installer, actual location will vary. Important to find out which chime is on before you go further.

[Skip426]

Dave, go to Class A MH discussion and find " My Labor Day Weekend Whatzit " by USMCRET and check out the picture and posts there for more info.