My gauge started going erratic a month ago and I have checked all the connections and have come up empty handed. Any help would be appreciated. It would be nice to have fixed prior to taking the 5th wheel camping in a few weeks.

 

This may or not help, but this is what worked for me. I have an Autometer pyrometer that became erratic. I checked all of the connections and they were all good. I called the Autometer tech line and the tech told me to hook the ground "directly" to the battery. I did this and problem solved. I hope this works for you.
John

 

I have 5 EV2 gauges, once a couple of yrs ago my trans gauge got stuck at some value for an hour, no problems since with it, but my boost gauge has an intermittent problem which I need to look at where it seems like 5 psi becomes the new zero for awhile.
Some things to check are for + 12v on pin 1 and chassis ground on pin 3 of each gauge, red and black wires and depending on the trans. temp. use an ohmmeter to measure the resistance between pins 4 and 5 at the gauge, green and white wires. You can find a temp. vs voltage chart on Isspro site, but at 60F it should be 17.3k ohms and at 70F,13.4k and 80F, 10.4k ohms.
If you have the attribute programmer software you can check the sweep of the gauge as it operates and set the red led value on a laptop, also check your wiring for nicks, cuts, chewed spots from mice etc. It could also be poor crimps at the connector to the trans. sensor itself or some conductive liquid maybe got into the connector like road salt ( unlikely I think).
The gauge should also home itself and read zero when you first turn on gauge power even with no temp probe connected otherwise the gauge is bad, you can check this on your truck or on a laptop.
when you check gauge voltages check at the pins at the back of the gauge ,not the wires at the pins.
Hope this helps you out.

 

Will do and thanks for all your help.

 

Looks like good advice above, best bet is to measure the resistance between the green and black sensor wires at the orange connector pins, and see if it matches the expected resistance shown in the chart of this troubleshooting document: http://www.isspro.com/TROUBLESHOOTIN...leshooting.pdf