So I bought a high idle switch a few years ago for my 99 ram. Worked great until last week. Now when I turn it on for my mpg fooler my check engine light comes on. It throws codes for the coolant temp sensor and the intake temp sensor circuit high. Not the first time I've seen this issue with this high idle switch. I'm a diesel tech here in South Dakota and one of my customers had the same switch and it did the same thing. I'm pretty sure the switch has gone bad. Just curious if any one has seen this issue as well. I'm sure I'm gonna have to replace the switch. I just don't feel like I should have to pay 150 bucks every three years for it. Thanks.

The answer to this greatly depends on which version of the switch you have?  Did you buy your switch through this site or from another source?   

 

Does the switch have a PCB board that it is attached to or is it Ed Graptons switch with the wires soldered directly to the back of the switch?

 

 

This is the newest revision.

 

The old version that Ed Grafton produced like @Me78569 said have the wires soldered to the back of the switch. Ed's design is prone to failure because of the weight of the cable pulling the contacts out of the switch. The new version removes the tension on the switch contacts being they are all soldered into a PCB. 

 

This is the older Ed Grafton series... Notice there is no PCB...

Edited June 18, 20177 yr by Mopar1973Man

Yeah it's the Ed Grafton version. I figured it was the switch.