Caterpillar C7 Engine Heater Not Working on 2004 Itasca Meridian 36G

[LPD218]

It appears my engine heater does not work. The cord has power and the switch works. May I am overthinking it. Does the engine heater have a thermostat that prevents 120 current when not needed?

I contacted a Cat dealership and they want $1500 to change it out. I can drain the coolant myself and install a new one if that is all it takes. 15 gallons I guess.

What re the chances it could be the cord that is detachable? I haven’t checked continuity yet through the cord.

2004 Itasca Meridian 36G

 

[Our ride]

No thermostat for heater.Check for continuity on the heater element itself after checking cord.

 

[Morich]

I don't think of thermostats, etc. as they are kind of meant for short term use to get started, but I get lots of surprises.
One other point to look at is how well the plug may be making contact in the outlet. Maybe be a bit paranoid and check the outlet with some other item like a light to try to sort out that the outlet and plug are not failing you if you are checking the heater for continuity. There are times when the bakelight that holds the plug contacts can get broken and be a nuisance to find as it can change every time we plug/unplug things!
If it all tests good but won't work, maybe consider plugging the heater into an extention cord to see if that changes the answer?

 

[LPD218]

Called the local metro Caterpillar truck center and was quoted $1500 for installing a new heater. I’ve changed regulators/thermostats and will do this myself once I get under the motor and check the failure of the heater.

 

[dickb46]

The heater wire plugs in at the electrical bay and then the wire plugs into the heater at the heater, check the cord.
Check both of the wire connections. I've never "had" to use the block heater .
ps your CAT C7 is 350 hp.

 

[dickb46]

unless you have a 3126, that's 330 hp, but they didn't put that in the 2004

 

[HiBanky]

A google AI search came back with this:
The engine block heater on a Caterpillar C7 engine typically has an electrical resistance between 12 and 20 ohms (for a 1000-watt or 1500-watt 120V heater)

With an Ohm meter, Check the resistance at the plug. Then be sure you have 120 volts at the receptacle.
This may sound like a dumb question but how do you know it's not working?

 

[Don G-WO]

On my 2005 journey I can see around an 8 amp increase when turning on the block heater.

 

[LPD218]

Don, I see no amp draws when I hit the switch. Used to. I checked power to the outlet with a fan. It has power. I got under the RV and the heater looks more than I want to tackle. Foley Truck quoted $1500 to install a new one. I’m going that way for the repair. Used to be able to do stuff like this, but don’t have it in me.

 

[LPD218]

Well duh! I guess there is a few seconds lag between when I turn on the switch and the amp draw I use catches up for this display. The heater works! Saved myself $$$$.

 

[Morich]

The more I look at things, the less I like complex things like monitor panels for getting good answers as they seem to have way too many tricks to play and too many connections between them and where I want to get the info.
One of the problems I have is that I like to know exactly WHERE that reading comes from and I can know that if I am sticking the probes on at some point. If the montor is telling me, I'm never sure it it testing at the same point where I want the info??

But on the other hand, CONGRATULATIONS on getting the right answer. It's not a mistake if you catch it before somebody else, right?

 

[LPD218]

I have a Bluetooth monitor on my surge protector and I forgot that there is a lag. Dummy me.

 

[FIRE UP]

unless you have a 3126, that's 330 hp, but they didn't put that in the 2004

They didn't put WHAT in the 2004??? In late 2003, Caterpillar introduced the C-7 which is the successor to the 3126. However, the change on the Freightliner assemblyline was not instantaneous. I have spoken with multiple 2004 Winne and Itasca owners with Freightliner chassis' and CAT engines and even with very close chassis ID numbers, the installation of a C-7 was infrequent as the 3126's were petering out. Our chassis was built in Oct of '03 and has one of the early C-7's installed.

LP218,
While you apparently got lucky and your block heater is still working, it might have been a wise choice to pay to have it replaced if it did fail. I've red a few reports on here and other RV forums about the nightmares of replacing the block heaters on either the 3126 (any version) or, its younger brother, the C-7. Basically, the mechanism that holds that block heater (which is almost nothing more than a residential water heater element) is what's called a "molly bolt". When the block heater is first installed and new, the bolt with nut on the outside you see, is tightened. When that happens, the inside components litteraly expand and clamp on the inside diameter of the bore. And the outside and inside sandwich the block and it's installed.

But, several years down the road and a few zillion miles and even with good antifreeze all the years and miles, those components get corroded and locked in place. So, just loosening the nut does absolutely nothing to "un-clamp" the internal components. You now have a fight on your hands and some have taken several hours to remedy this particular situation. I'm dreading it if and or when it happens to ours.
Scott