Community Forums

brennaman · 11-08-2024, 06:38 PM

I have a 2012 ISL9, 450HP engine. I can't find any information on the electric heater on the engine. I also have aquahot for heating the engine, but I am curious if there is more information on the electric heater. I know where the plug is that supplies 110 VAC to the heater, but when I measure across the plug it is open. Is there a thermostat that will allow the heater to get power if the temperature is below a certain temperature. I turned on the electric heater, and did not see any increase in current draw, so I do not think it is getting turned on. (that is why I measured across the plug to see if I could see if the heater is open) The RV is in a climate controled storage, so the temp is about 65 degrees. Maybe that is why it won't turn on, if so, where is the thermostat, and more importantly where is the heater located? Probably will never have to use it, but I would like to know a little more about it if I ever do need it.

Thanks Phil

jacwjames · 11-08-2024, 07:39 PM

Do you have an electrical schematic for your coach, it should show the block heater and how it might be turned on/off and whether there is a thermal switch.

I have one on my coach but it is actually turned on off from a 12 volt switch on the dash. There is a 12volt to 120 volt relay that turns on the heater.

**Lt Dan** · 11-08-2024, 08:43 PM

On your Tiffin Bus you should have a switch on the dash that turns the power on to that outlet where the block heater is plugged in.

brennaman · 11-08-2024, 09:54 PM

I do have a switch on the dash, but I can't find the heater and it's circuitry anywhere in my drawings.

The outlet that has a plug in it labeled engine heater, has a constant 110 VAC. The switch on the dash does not control that outlet.

I am thinking I will have to contact Tiffiin, and they could provide the drawing for the heater. Or should I look towards Cummins, and they would have the drawing for the heater.

Hope I explained that well enough, Phil

SafariBen · 11-08-2024, 10:42 PM

I've never seen a thermostatic block heater, only tank types. Block heaters usually have a removeable cord, so you can check the element directly with an ohmeter, something like 10-20 ohms. If all else fails, trace the cord or find the heater and trace from there. Seems like the block heaters are mostly 3/4" npt and usually threaded into the thermostat housing or oil cooler (oil filter mount) area. might vary depending on what's on the engine. I wouldn't think many block heaters get used much to burn out, but anything's possible. My 8.3 CTA came with two intake manifold flame starts with cummins part numbers and controller, so anything's possible...

brennaman · 11-09-2024, 06:26 AM

Quote:

Originally Posted by SafariBen

I've never seen a thermostatic block heater, only tank types. Block heaters usually have a removeable cord, so you can check the element directly with an ohmeter, something like 10-20 ohms. If all else fails, trace the cord or find the heater and trace from there. Seems like the block heaters are mostly 3/4" npt and usually threaded into the thermostat housing or oil cooler (oil filter mount) area. might vary depending on what's on the engine. I wouldn't think many block heaters get used much to burn out, but anything's possible. My 8.3 CTA came with two intake manifold flame starts with cummins part numbers and controller, so anything's possible...

I know where the end of the removable cord is, and I did check it, it reads infinite. That is why I am trying to locate the heater. Also, the outlet my heater is plugged into is always on (constant 110 VAC) this is why I would like to find any info on the circuitry.

I will call Tiffin on Mon. thanks all Phil

brennaman · 11-09-2024, 06:29 AM

Quote:

Originally Posted by jacwjames

Do you have an electrical schematic for your coach, it should show the block heater and how it might be turned on/off and whether there is a thermal switch.

I have one on my coach but it is actually turned on off from a 12 volt switch on the dash. There is a 12volt to 120 volt relay that turns on the heater.

Sorry I did not address your question. Yes I do have the electrical schematic, but all it shows is the wiring to the outlet the heater is plugged into. It is just off a breaker, and has a constant 110 VAC. I did not see the wiring for the block heater switch that is on the dash that turns the block heater on.

thanks Phil

jacwjames · 11-09-2024, 08:54 AM

Not a problem.

If you have a switch on the dash for the block heater it is probably 12 volt meaning there has to be a 12/120volt relay. Could be mounted anywhere, I seen pictures where they were mounted in the main service panel enclosure visible when you remove the front cover.

In my case I have two systems controlled by the relay, one for the block heater and one for the water heater. Both relays are mounted in a separate small 6X6 box mount behind the main panel, very difficult to get to and see.

So you might pull the cover off your service panel that has the circuit breaker in and and see how it is wired. Might have to buy a wire tracer and follow the circuit.

brennaman · 11-09-2024, 09:16 AM

Quote:

Originally Posted by jacwjames

Not a problem.

If you have a switch on the dash for the block heater it is probably 12 volt meaning there has to be a 12/120volt relay. Could be mounted anywhere, I seen pictures where they were mounted in the main service panel enclosure visible when you remove the front cover.

In my case I have two systems controlled by the relay, one for the block heater and one for the water heater. Both relays are mounted in a separate small 6X6 box mount behind the main panel, very difficult to get to and see.

So you might pull the cover off your service panel that has the circuit breaker in and and see how it is wired. Might have to buy a wire tracer and follow the circuit.

I have been looking, these manf. seem to be good at hiding some things sometimes.

This is kind of a low on my list item right now, like I said I don't travel much in cold weather, and I do have the aquahot block heater. I think at this point I will contact tiffin and help get me going in the right direction.

Thanks all for the advice, Phil

96 Wideglide · 11-09-2024, 12:32 PM

I've never bothered using the electric block heater!

If I'm traveling in cold weather, I'm gona want the interior warm as well, so, AH takes care of both.

jacwjames · 11-09-2024, 01:17 PM

I've owned my coach for 16 years and only last month used the block heater. I was in NV and it snowed one night and when I tried to start the engine it was very sluggish, it started ran for ~10 seconds and died. Restarted and it was fine but no doubt the cold weather made it harder to start.

So the next time I was in cold weather the night before I turned the switch of the dash on and let the block heater do it's thing. The rig started right up.

Wish I had an AH system, but I get by.

SafariBen · 11-09-2024, 02:55 PM

If it ever matters, you get 80% of the benefit in 30 minutes, and 95+% in an hour. Leaving the block heater over night is just keeping the engine warm, it's not getting more than a few degrees warmer than in the first hour.

Skip426 · 11-09-2024, 03:17 PM

The engine block heater on your ISL will probably be close to the oil filter ( transmission side ) , and have knurled retaining nut to hold the cord to the heater .

This picture of an ISB with exhaust manifold and turbo off shows location and connection . Yellow arrow.

brennaman · 11-09-2024, 04:48 PM

Quote:

Originally Posted by Skip426

The engine block heater on your ISL will probably be close to the oil filter ( transmission side ) , and have knurled retaining nut to hold the cord to the heater .

This picture of an ISB with exhaust manifold and turbo off shows location and connection . Yellow arrow.

Thanks, that helps a bunch. Phil