Slides and leveling jacks not working

[Roninarv]

Hi everyone Ron here and a newbie to this forum, I have a class A 2003 national Highlander 9403 40 foot long with two slides and with the 400 Cummins engine. The problem I am having is that my slides and my leveling jacks will not operate when the air park brake light on the dashboard is not on. Sometimes when I go to park and I hit the airbrake parking brake the light on the dash that says park Break, then the slides and the jacks will work. Then sometimes I pull the air park brake and the light does not come on on the dash that says The parking brake is on, at that point the slides and the leveling jacks will not operate. I have changed the motherboard and I have checked all the fuses and have changed all the relays and replaced the Air brake switch. I am at a loss for what to do at this point, any help for this problem I am having would be greatly appreciated. Thank you in advance for any information on this problem.
Ron

Slides and leveling jacks not working

[ArkansasRomr]

A few questions

It sounds as if you are at least fairly handy with electronics. The leveling jacks, are you referring to the actual HWH jacks or do you use your air bag suspension to level your rig? The slides are designed to not operate unless the rig is set to park and probably engine not running. These are safety features that I’m sure most rigs share.

I’m sorry for lack of answers but there’s a lot of knowledge on this forum and someone will come along. In the meantime I will think it over again as I had a similar issue before.

[VanDiemen23]

Yup. That's a safety lockout. I'm sure you can find the relay and bypass it, but it's not a good idea. You come down off the jacks and start rolling.....

Why is that feature a problem for you?

[CountryB]

Originally Posted by Roninarv

\Sometimes when I go to park and I hit the airbrake parking brake the light on the dash that says park Break, then the slides and the jacks will work.

Then sometimes I pull the air park brake and the light does not come on on the dash that says The parking brake is on, at that point the slides and the leveling jacks will not operate.

I suspect the parking brake electrical switch is not working properly. This switch is usually threaded into the parking brake valve at the dash brake valve. For the small cost of the switch, I would replace it (if a new switch doesn't fix the problem at least you will have eliminated one possibility).

This switch is "normally closed" (power goes through switch with no air pressure on the switch, and the "Parking Brake On" light then illuminates) then when you release the parking brake (apply air pressure to the spring bakes and to the switch, it opens which turns off the dash light).

[RKins]

On my rig there is an interlock switch on the bottom of the drivers seat that closes when the seat is straight forward. The switch being open stops the slide from operating - maybe you have something like this too? As others have asked - please tell us the manuf of the levelers.