OEM Block Heater

[prossett]

No issues starting in the cold, but I have the 3-waves button on the dash, and so I'd like to make it work.



When I click it, nothing happens.

There is a muffler underneath, driver's side.

I saw this thread with a good video for the T1N, but couldn't find much for the NCV3.

Would this be the Espar heater I've seen mentioned?

I think it works only below a certain temperature, so I'd like to check this before the weather warms up.

Could someone kindly guide me?

 

[Kajtek1]

Is that the only active switch on this subpanel?
Usually they are combined with high idle.
Start with checking DataCard with your VIN, to see what version of heater you have.
Most likely it is H5 heater, who will not activate above certain temperature. I remember it to be in like 36F, but my memory can be wrong.
H5 need engine running and dash heating on.
Not sure about parking brake, but better have it on.

 

[prossett]

Yes, it's the only active switch.

From the datasheet, I find:

HH2 - ELECTRICALLY POWERED HOT-AIR AUXILIARY HEATER

HH9 - SEMI-AUTOMATICALLY CONTROLLED TEMPMATIC A/C

HZ9 - HEATER BOOSTER, DIESEL

and there's also reference to

KL1 - FUEL-LEVEL SENSOR FOR AUXILIARY HEATER

There was also a Webasto style diesel heater in the cargo area, connected with a fuel line to the diesel tank - but the installation looks sloppy aftermarket, so I think it was added later.

 

[prossett]

Further to deciphering the datasheet (great suggestion - thanks!) Google says :

The HH2 option is an
electrically powered PTC (Positive Temperature Coefficient) booster heater designed for Mercedes-Benz Sprinter vans to accelerate cabin warm-up. Unlike fuel-fired systems, this electric heater operates when the engine is running to provide faster heat, improving comfort and window defrosting in cold conditions.

The HZ9 Diesel Heater Booster is a 5kW (17,000 BTU) auxiliary fuel-fired coolant heater option for Mercedes-Benz Sprinter vans. It aids engine warm-up and cabin heating in cold weather, usually by heating the coolant loop while the engine is running or as a parked pre-heater, often controlled via a dashboard button.

So it seems like the HZ9 is what I need to test.

 

[Maslin]

They only work under 39 degrees or something. Basically impossible to test outside of that, people have swapped resistors in place of the ambient temp sensor.

 

[prossett]

Thanks. Tomorrow morning I'll run out, wooly hat and mittens, and see what I can do - should be well under 39F!

What should I test for, after I click the dash switch?

 

[Maslin]

It should fire off that heater and get the coolant moving. Beyond that, I’d be checking for faults.

 

[prossett]

OK, thanks - no faults, so hopefully it just wasn't cold enough when I tried it, and tomorrow the little light should come on

(and I can let it relax until next winter 😀)

 

[Kajtek1]

Yes, it's the only active switch.

From the datasheet, I find:

HH2 - ELECTRICALLY POWERED HOT-AIR AUXILIARY HEATER

HH9 - SEMI-AUTOMATICALLY CONTROLLED TEMPMATIC A/C

HZ9 - HEATER BOOSTER, DIESEL

and there's also reference to

KL1 - FUEL-LEVEL SENSOR FOR AUXILIARY HEATER

There was also a Webasto style diesel heater in the cargo area, connected with a fuel line to the diesel tank - but the installation looks sloppy aftermarket, so I think it was added later.

So HZ9 would be what you are talking about.
HH2 is electric heater in your dashboard, who comes with Tempmatic (HH9) setting and doesn't have additional switch.
I had HZ9 (remember it as H5, what might be different MY) in my 2015 Sprinter and found it basically useless.
I think the only use for it would be city driving, when engine is not generating lot of heat and temperatures below -10F.
I drove in temperatures below 0 and at 70 mph the engine gives enough heat to keep extended van comfortable.
Bear in mind, factory buses don't have much insulation.

 

[Cheyenne]

There was also a Webasto style diesel heater in the cargo area, connected with a fuel line to the diesel tank - but the installation looks sloppy aftermarket, so I think it was added later.

It is quite likely that the original fuel line from the tank to the factory fitted Espar heater has been disconnected and used for the aftermarket Webasto heater. Crawl under the van and look at the fuel pipes near the fuel filler pipe at the tank.

 

[prossett]

Well, I 'solved' the required temperature parameter, as it was freezing out today!

-6C / 20F, but no little light came on.

Once I was there, enjoying the frozen wasteland of southern Ontario in April, I lost all appetite for going under and tracing fuel lines, but I agree with @Cheyenne - makes good sense that the existing fuel line was re-routed to the back heater, where the workshop was.

I'll have a good look when I regain the use of my fingertips.

 

[dharmasprint]

Actually, the switch means that you get 3 more strips of bacon when the light goes on!

Seriously, it may be coded out or the fuse might have been removed. On my 2011, the light would come on when the switch was pressed regardless of the temperature but would only activate if temperature was below the threshold and the fuel tank was above the 100 km reserve level.

 

[mikeh08sprinter]

MY 2008 has all of the same info on my data sheet. I have the same single button to the left of my dash I also have the heater outside under the driver seat and i have never got mine to kick on. no matter how cold it is. I've even taken my sensor out (by the front license plate) and placed it in ice water and it has never come on. I've told myself at this point its just for looks. lol

 

[prossett]

Yes, I won't miss it - but would be interested in it working as it should, just because it's there 😄

Or maybe turn it into a coffee maker...

If it could crisp 3 rashers of bacon and brew hot coffee on the go, it would become the most prized piece of kit in the Sprinter!!!

 

[mikeh08sprinter]

Yes, I won't miss it - but would be interested in it working as it should, just because it's there 😄

Or maybe turn it into a coffee maker...

If it could crisp 3 rashers of bacon and brew hot coffee on the go, it would become the most prized piece of kit in the Sprinter!!!

I'd like mine to work too.

 

[prossett]

Strange there's no fault displayed, though.

I think that since there's no light on the switch itself when clicked, that would be the first thing to check. And looking for the fuse, though I'm pretty sure all are ok, last I went through them.

So maybe a faulty switch?

Great idea the freezing cold water for the temperature sensor!

When it gets warmer and I'm ready to also check on the rear heater at the same time, I'll go under and see what connected to it, in case there's no fuel line or something obvious.

 

[mikeh08sprinter]

Strange there's no fault displayed, though.

I think that since there's no light on the switch itself when clicked, that would be the first thing to check. And looking for the fuse, though I'm pretty sure all are ok, last I went through them.

So maybe a faulty switch?

Great idea the freezing cold water for the temperature sensor!

When it gets warmer and I'm ready to also check on the rear heater at the same time, I'll go under and see what connected to it, in case there's no fuel line or something obvious.

I have no faults/CEL either. My red light on the switch has never illuminated either. some sprinters have more than 1 switch when it comes to that heater I've also noticed in the past.

 

[Maslin]

Are there faults in the control unit itself? It's never going to set a check engine light.

 

[mikeh08sprinter]

Are there faults in the control unit itself? It's never going to set a check engine light.

how does one check for faults on the espar heater?

 

[Maslin]

how does one check for faults on the espar heater?

There's a control unit, you would need Xentry or one of the more powerful aftermarket scanners.