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Topic: Rear air pressure gauge (Read 898 times) previous topic - next topic

Rear air pressure gauge

Good morning
My rear air pressure gauge keeps on cycling between what I hope is the correct air pressure, which is matching the Front air pressure gauge,
And pegging out at 150.
Is there something I can do to fix The gauge or do I just need a brand new gauge?
I've been trying to find a part number but have been unsuccessful.
Thanks
Frank & Daisy
NO LONGER  "looking for the perfect Foretravel
36' or less non slide preferred."  She has been found and is ours.
2003 U320 36' non slide  Unit 6103
Cummins ISM 450
Allison 4000MH

Re: Rear air pressure gauge

Reply #1 –
Search (on the Forum) the term "blue module failure" for info.  Here is one hit to get you started:

"Blue Module" Failure
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Rear air pressure gauge

Reply #2 –
Frank, your pressure gauges are electronic and display a value based on a reading from a pressure transducer located at the tank.  The transducer uses 0-5 volts that comes from the blue box. The transducer provides resistance based on pressure to vary the voltage returning to the blue box.  If the gauge reads zero then it is getting zero volts. The alarm should be dinging. This is what happens most often when the blue box fails.If it reads max pressure then it is getting 5 volts.  I would check the wiring first.  If there is enough wire switch the front and rear tank wiring and see if the behavior switches.  It could be a bad or dirty connection or a shorted out transducer.

Mine failed, both gauges went to zero and the alarm annunciator dinged for two days before I figured out how to stop that. I replaced my OEM gauges with VDO Air Pressure gauges that read the pressure directly from the tank.  They connect to the tank with a piece of tubing to a fitting on the tank where the transducer was.  I used 1/4" tube, 1/8" will work fine.  This will not stop the dinging, you may be able to add a switch to turn it off, that is what I did. Then you can wire around the switch with a couple diodes so that the dinger works again with the turn signals.  I like the direct read gauges,  even with the engine off they show tank pressure.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Rear air pressure gauge

Reply #3 –
Thank you both for your replies. When I posted this morning I was sitting outside the Cummins service center in Albany, GA.
I got an oil & filter change along with two fuel filters. My coolant was good so nothing done there.
What's funny is that I drove the coach another 220 miles and it didn't do it once.
Frank & Daisy
NO LONGER  "looking for the perfect Foretravel
36' or less non slide preferred."  She has been found and is ours.
2003 U320 36' non slide  Unit 6103
Cummins ISM 450
Allison 4000MH

Re: Rear air pressure gauge

Reply #4 –
Quote from: Lt403 –
What's funny is that I drove the coach another 220 miles and it didn't do it once.
Typical "intermittent electrical gremlin".

Take it to a mechanic or shop, and they will say "Unable to reproduce the defect"...then they will charge you $120.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Rear air pressure gauge

Reply #5 –
Sounds like a bad pressure transducer.  Clean the connections at the tank.  Put some dielectric gears on the connection to keep it clean.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Rear air pressure gauge

Reply #6 –
Just curious, where does this blue module live on the coach? Just would like to know for future Reference



Keith
The selected media item is not currently available.Keith & Jo
2003 U320T 4025 PBBS Designer series
Build 6203    Cummins 500hp
2000 U320 4010 WTFE / Build 5762 —Sold—
Motorcade #18070   
Pasadena, Texas
2015 Jeep Wrangler Sahara-Sunset Orange pearl coat
Don't argue with a fool, people watching might not be able to tell the difference.

Re: Rear air pressure gauge

Reply #7 –
Should be under your dash. Taking off the curved piece and looking down at all the wires you should find it.
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: Rear air pressure gauge

Reply #8 –
In our 2001 the blue box is gray.  Start with any wire from a dash gauge and follow it back to the box.  Keith, yours might be different.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Rear air pressure gauge

Reply #9 –
Thanks roger, with the glass dash it probably is.


Keith
The selected media item is not currently available.Keith & Jo
2003 U320T 4025 PBBS Designer series
Build 6203    Cummins 500hp
2000 U320 4010 WTFE / Build 5762 —Sold—
Motorcade #18070   
Pasadena, Texas
2015 Jeep Wrangler Sahara-Sunset Orange pearl coat
Don't argue with a fool, people watching might not be able to tell the difference.