Freightliner Air Bag issue

Just finished by drive last night

I fired up the RV Monday morning and tuesday morning and the air gauge showed 120 psi both days and worked all the way through the trip.

Another Ghost in the machine.

Thanks for the help guys!

Lakebum has given you good advice. The Freightliner Help Desk is a free service and they are very helpful.

You are getting good advice for generic truck systems from the other posters, but it does not apply well to the Freightliner system of dash gauges for the RV chassis.

In the 1999-2003/2004 era, Freightliner used a Vehicle Data Computer to collect data from the engine computer and transmission computer, to measure air pressure (two ports) and to send this data down a data bus to the dash gauges. Somewhere around 2003/2004, they changed to a different system, but it has some similar features.

I'd guess that you have a bad vehicle data computer or bad connection in the system. The 1999 - 2003/2004 VDC's had a history of cold solder joints that could cause your problem.

The Freightliner Help Desk is your best bet for good advice for your problem.

There is some additional reading info available in the Freightliner Chassis forum on the IRV2 website. If the Freightliner Help Desk thinks you have the old VDC type system and that cold solder joints is a possibility, many have cured that problem with careful use of a soldering iron. I believe that info is on the IRV2 web site. If not, send me a PM and I can send it to you.

Fred

Those pressure readings are unlikely to be for the bags. They are actually monitoring the brake pressure tanks.

supercub wrote:
Can you switch the lines going into the gauges? If so, you'll find out fast if it's a gauge or not.

Sure. With engine off, brakes set, pump down to zero. Swap gauges, all air lines will have to be hooked up, do not mix up. Fire her up and see. If readings are reversed, bingo, bad gauge.

150 lbs is way to high. You better make sure that it is a faulty gauge because if not it could be big problems.

Can you switch the lines going into the gauges? If so, you'll find out fast if it's a gauge or not.

wolfe10 wrote:

J&R wrote:
Most air compressors cut out about 120psi. So 150psi not possible.

While I agree most systems do have a cut-out PSI of about 120 PSI, a defective GOVERNOR could make it go higher.

But, I agree with earlier posts, this is very likely a gauge, not PSI issue.

Agree, but as the poster stated the front bags were 120psi and he could hear compressor cutting out. It appeared governor was working. If all gauges were showing 150psi, malfunctioning air governer, or blown air line, etc.

Thanks guys, my thoughts as well, air system functions as it always has, just the gauge is showing a higher PSI.

I like confirmation.

J&R wrote:
Most air compressors cut out about 120psi. So 150psi not possible.

While I agree most systems do have a cut-out PSI of about 120 PSI, a defective GOVERNOR could make it go higher.

But, I agree with earlier posts, this is very likely a gauge, not PSI issue.

Most air compressors cut out about 120psi. So 150psi not possible.