Robert U Posted July 16, 2021 Share Posted July 16, 2021 I am having a intermittent warning light on my 2000 Diplomat ISC8.3 315hp. My coolant temp is running at 189 degrees normal. When I climb a hill the temp will climb to about 191 to193 degrees and the warning light may come on. Radiator is new and clean. Coolant level is OK. Wiring diagram shows coolant sensor going directly to dash gauge and not to ECM. Is there a second sensor on the engine wired to the ECM and if so where is it located on the engine ? Bob U Link to comment Share on other sites More sharing options...
Dr4Film Posted July 16, 2021 Share Posted July 16, 2021 Your coolant temps are WELL within the normal range so I don't believe that is contributing to your "warning light" issue. Possibly your coolant level sensor needs to be cleaned and polished. Link to comment Share on other sites More sharing options...
Robert U Posted July 16, 2021 Author Share Posted July 16, 2021 . I need to find Richard Low coolant sensor is wired to low coolant light on dash. It is not coming on. There has to be a second sensor on the engine wired directly to the ECM. therefore it would not show on Monaco wiring schematic. I know that there is also a separate sensor for oil pressure on the engine witch is wired to ECM. I need to find the sensor for coolant temp. Bob U Link to comment Share on other sites More sharing options...
Hancoman Posted July 16, 2021 Share Posted July 16, 2021 Good luck, my warning light came on and never went off. I had engine service all fluids topped off, coolant level sensor cleaned and polished to no avail, light still on. I have driven the coach from Washington State to South Carolina and back coach performed flawlessly with warning light still shining brightly. I will be interested to see if you find a solution Tom C Link to comment Share on other sites More sharing options...
vanwill52 Posted July 17, 2021 Share Posted July 17, 2021 Do you have a generic "WARNING" light on your instrument panel? If so, it may come on for a variety of reasons. If you have that generic warning light, I have more info for you. Link to comment Share on other sites More sharing options...
Robert U Posted July 17, 2021 Author Share Posted July 17, 2021 Van, I have a generic warning lite. It can be set by coolant temp, oil pressure, intake manifold temp, engine overspeed, and fuel temp. I suspect coolant temp because it only happens when temp gauge on dash goes up a few degrees. I may have to have the codes pulled by the diesel mechanic that I use.He charges one hour at $140/hr. There has got to be a second sensor for coolant to set a warning lite. I would like to hear your take on the warning lite. Thanks Bob U 2000 Dip Link to comment Share on other sites More sharing options...
vanwill52 Posted July 17, 2021 Share Posted July 17, 2021 Bob, your warning light can be triggered by a multitude of errors. You can only determine which one it is by having the codes read. If ANY warning in the Cummins universe is triggered, the ubiquitous "Warning" light comes on. A VMS-PC will interpret most codes, as will the ScanGage product, but they usually report a "Generic" code that is not the same as the Cummins code. One would think that a Cummins tech could be the best bet for analyzing a code. In my case, that was not true. I had a code registering on my VMS-PC for literally three years that a Cummins tech could not interpret, even when he plugged directly into my ECM, using INSITE from under the coach. I have forgotten the code number (although I think it was "Generic" 151) but the English language interpretation was "Power supply voltage invalid". Since Cummins could not read the code from my ECM, I just ignored it. Three years later, the code reared its ugly head in reality. It turns out the code was for a power supply problem in the ECM. The code was that the ECM was failing, but took three years to finally crap out completely. When it finally failed completely, the ECM had to be replaced with a "remanufactured" (cleaned and painted used ECM) from Cummins. Total cost was over $7K, using an unusually talented shop in the Atlanta area. The shop was MTR Motor Fleet Services (mtrfleetservices.com) in Cumming, GA. Jason Martin is the owner, and is a talented, Christian young man. Had I been able to get an interpretation of the code, PERHAPS I might have scheduled the ECM replacement at a more convenient time. As it turned out, Paul Whittle (Sh*tter Whittle, the OPUS toilet electronic guru) put me up for nearly three weeks while the diagnostic/replacement routine took place. Kudos to Paul and Barb who are always ready and willing to help folks with MH problems. Thanks also to Frank McElroy, who is a Cummins ECM expert, and also an expert on all things Monaco that are electric/electronic. Moral of the story--find a way to get your codes read, so you have a clue what calamity may be awaiting you around the corner. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now