I have the Air Zenith 220 PSI Digital Air Gauge on my truck and this will be the third time I’ve needed to replace the sending unit (I bought extras for my other trucks).
Is this a known issue with them? I’m reading 90 to 130 PSI lower than my manual gauge on the tank itself.
-Kris
Hey M.O, daft question, are you sure it’s not a grounding issue? I have one and it’s really really voltage sensitive and needs a proper clean ground?
Yeah the ground is good. I share it with the pressure switch, and I’ve even used my Dremel to clean it up before I swapped it out the first time thinking it might be the problem.
Figured I’d test it again, so I dropped the digital voltmeter and then a test light on it to confirm it was still good. I painted over it to prevent corrosion with some Rustoleum after the first swap and we’re still working great.
I even replaced the connectors at the sending unit, just to make sure. Still shows a maximum pressure of 58 PSI, which is about 110 off.
-Kris
The sending unit isn’t plugged up somehow is it? Just a though… Idk if that would affect anything
I think they don’t have a good life span. I’ll test the old one out this weekend if I get a chance and see what happens.
Maybe it’s time to consider a setup from Dakota Digital.
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=389/category_id=-1/mode=prod/prd389.htm
I’ve got the 0-400 PSI sending unit (since I run a 200psi air system) and it’s been installed in my pneumatic manifold under the hood for a year, now. I’ve had not a single issue with it, to date … but keep in mind mine’s not really exposed to the elements, as it’s in the engine compartment … so heat and water from road spray is about all it has to deal with. That’s intentional on my part, by the way, as I don’t expect electronics to hold up for very long when exposed to road debris, road tar/solvents, brine, and other things the undersides of vehicles regularly see – so I made sure not to put my pressure switch and sending unit in such a place. 
Worth mentioning is that I went this route instead of using an Air Zenith specifically because when researching electronic gauges I read a number of reviews complaining about Air Zenith sending unit issues … from off readings to complete failures. The Dakota solution was more expensive … but had/has a 24-month warranty on it. So far it’s proven itself to me.
Note that you can program the Dakota Digital guage with both low and high pressure thresholds – and it’ll flash the air pressure reading when below or above the low or high threshold, respectively. The guage also has dimmer support. You’re out of luck if you want a colour other than blue or teal…
Also note that resolution is 1psi for the 0-150psi sending unit … versus 2psi for the 0-400psi sending unit. I missed that tidbit when ordering, so I initially thought something was wrong when the 0-400psi unit would only display in 2psi increments.
And no, I don’t work for Dakota … I’m just a happy customer.
Cool, I’ll check that out … thanks!
Swapped the old sender out, same problem. I didn’t have time to find my spare (my lovely wife reorganized some stuff in the garage) before heading out to a UTV demo ride on Saturday. Had a blast … I might look into a nitrogen tank setup for this and a set of Shockers or the horns from the Katrina kit if the wife lets me get it. I’ve already picked up a search light for it, and I’m looking into switching it from halogen to HID.