Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Speedup on August 02, 2022, 08:25:26 am

Title: Dash air gage reading 0
Post by: Speedup on August 02, 2022, 08:25:26 am
2003 GV320 what would cause front dash air gage intermittently reding 0 while driving
while driving head home this weekend after 30 minutes of driving gage went to 0 .
so I pulled over and checked for air leaks ,no air leaks found, brakes ok.
5 minutes later ,gage back to normal buzzer stop , air gage normal for rest of trip
thinking maybe bad sensor .
where would the front air sensor  be found ?
Title: Re: Dash air gage reading 0
Post by: Chuck & Jeannie on August 02, 2022, 08:52:48 am
Speedy,

Your air pressure gauges are electronic.  They are driven by a signal from a mysterious blue (or gray) box hidden up under your dash.  If you have air pressure in the tanks and the gauge says zero, then good chance the intermittent fault is in the blue box.  Photo of a typical "blue box" below.

Search the Forum for the term "blue box" to see previous discussions of this subject.  Here are a couple threads to get you started:

Intermittent gauges (https://www.foreforums.com/index.php?topic=42753)

02 U320 Air gauge stopped working (https://www.foreforums.com/index.php?topic=37921)

Title: Re: Dash air gage reading 0
Post by: dsd on August 02, 2022, 09:44:06 am
So both your senders are on there respective air tank. I had the same problem on my coach. You can swap the air pressure senders and verify that the problem follows to the other position, bad sensor or if it stays in the same position it is as Chuck has described. Ive actually have changed three senders in the past two years, but currently working normally.
https://www.summitracing.com/parts/SWW-82894
They had them cheapest and were outstanding on replacing the failed new one without issue. Super fast. Shipping also
Scott
Ive also still been talking to One Gauge about a replacement system since Steward Warner no longer supports our coach system, Im hoping eventually we will have a affordable replacement/upgrade for these systems
Title: Re: Dash air gage reading 0
Post by: Elliott on August 02, 2022, 10:06:17 am
Start with diagnosing the senders and then work your way to the magic blue box. It'll take you longer to raise and block the coach than to swap the senders. Get yourself some colored zip ties to mark what goes where before you move things around.

It is going all the way and bottoming out at zero, and in only one gauge correct?
Title: Re: Dash air gage reading 0
Post by: Speedup on August 02, 2022, 10:25:39 am
yes one gage only, it reads 0 or 105 to 125 nothing below 105
there are no sensors on air tanks. looks like front and rear air tanks are connected directly to blue box under dash
with 1/4" air lines
Title: Re: Dash air gage reading 0
Post by: oldguy on August 02, 2022, 10:27:22 am
I had a sender go when I had the Monaco. Got a new one at Napa and was good to
go.
Title: Re: Dash air gage reading 0
Post by: dsd on August 02, 2022, 11:02:23 am
yes one gage only, it reads 0 or 105 to 125 nothing below 105
there are no sensors on air tanks. looks like front and rear air tanks are connected directly to blue box under dash
with 1/4" air lines
That kinda changes everything. If your able to find a place that will repair your box, please post so other may use. I never did find anyone but am a firm believer that if some one built it someone can repair it. Just. Need to find that one someone. Others will post to just add direct reading pressure gauges and this will work but you loose the low pressure warning and would have to install additional low pressure switches to work around.
Scott
Title: Re: Dash air gage reading 0
Post by: Chuck & Jeannie on August 02, 2022, 12:01:33 pm
Wouldn't hurt to unplug the electrical connector on the blue box, check for any sign of damage, then reconnect the plug.  If you can follow the wires from the box to the gauges check for anyplace the wire insulation could be damaged or cut.  If the gauges have a separate ground wire make sure it is seeing a good connection to ground.
Title: Re: Dash air gage reading 0
Post by: dsd on August 02, 2022, 12:09:58 pm
So my gauge converter has been wonky on the Oil reassure indicator. Would chime low oil pressure and indicate all over the place. Once I started using secondary indication, silverleaf or bluefire and saw a good stable indication I basically have not paid attention to the factory gauge. I would like it to work but once again if I can sort out the One gauge similar to the Bronco that will be my resolution. I really should take a peak inside the converter, possibly its just some bad capacitors?
Scott
Title: Re: Dash air gage reading 0
Post by: Elliott on August 02, 2022, 12:24:20 pm
looks like front and rear air tanks are connected directly to blue box under dash
with 1/4" air lines
Hm, mine are on the curb side of the air tanks like Scott suggests. This is good news at the end of the day though... makes going directly to mechanical gauges much easier for you since the airline is already mostly run. IIRC, Roger has a post somewhere with part numbers for the gauges he used. Inline pressure switches wired to low-pressure alarms are a good idea.

Hopefully it's just a poor connection though...that'd be nice
Title: Re: Dash air gage reading 0
Post by: Chuck & Jeannie on August 02, 2022, 02:50:30 pm
Roger has a post somewhere with part numbers for the gauges he used.
02 U320 Air gauge stopped working (https://www.foreforums.com/index.php?topic=37921.msg366674#msg366674)