# Hymer Controls



## Raggy (Dec 16, 2007)

I need some help... have a button/switch on dash,but have no idea what it does!! only owned motor-home for 1 1/2 years and now decided i would really like to know what it for. Motor-home is an 2001 Hymer S650 on mercedes chasis, button/switch looks like an original mercedes part but vehicle has just been serviced by mercedes and they don't know either.. think it could be to do with the heating system?? Any one got a manual/handbook for this particular model?


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## richardjames (Feb 1, 2006)

It looks like a Merc dash and the control is for a burner to help warm up the engine. It is not a pre-heater and on the 316 the control has two above and below one to switch on A/C and the top segment provides heat whilst stationary!! If you look underneath the engine on the nearside (if it's RHD) you will see an exhaust pipe pointing down to the ground. To sum up when switched on it speeds up the warm up time (if its working)


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## peejay (May 10, 2005)

Could be wrong (usually am) but its possibly some kind of auxillary heater, Webasto perhaps for the habitation area, hence Mercedes not knowing what it is(?).

Peet


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## jemshome (Nov 10, 2007)

Straight from the Mercedes Sprinter Manual ...

*Heater booster (only with auxiliary water heater)*

The switch (the centre knob) for activating the heater booster system is located in the centre of the dashboard.

The heater booster system can be switched on while the vehicle is being driven to help the engine reach its normal operating temperature more quickly, which will help to heat up the passenger compartment as quickly as possible when the heating is switched on.

To switch on with the engine running, press the centre knob - the indicator lamp lights up (as you show in the jpg)

To switch off - press the knob again or switch the engine off. The heater booster will then switch to run-on mode (approx. 120 seconds).

*Notes:*

When the vehicle is being driven and a coolant temperature of over 80 deg C is reached, the heater booster system will switch to regulation mode. If the coolant temperature drops below 75 deg C with the heater booster system switched on, heat output is increased again.

If the key is turned to position 0 in the ignition lock (run on for approximately 120 seconds), the last setting selected is retained when the engine is restarted (memory function).

The heater booster system is not normally required at outside temperatures of above +5 deg C.

Hope this helps ...

This is straight from the manual - I would be a bit unhappy if a Mercedes service engineer didn't know/or didn't at least go and make some enquires.

jem


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## Raggy (Dec 16, 2007)

Many thanks for replies... guess I will wait for the colder weather to see if it works as described... thanks..


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## trek (May 1, 2005)

Why wait for the cold weather to test it

It will work if you start your engine , put the heater temp to max i.e hot and press the button for the heater booster

after a short while you should hear a roar from under the front nearside of the van and after a little time you should be able to smell the exhaust gas from its own exhaust pipe

(it make take a while for the diesel to get pumped through if you have never used it ( & it won't work if the fuel is low in the tank)

more info here:-

http://www.espar.com/documents/sprinter_manual.pdf

This can be a useful item in the cold - I would use it to bring the engine up to working temp quickly (& of course the cab heater)

Ideal if you go skiing as when descending from the slopes down into the valley the engine will take forever to warm up while you freeze inside, with this problem solved

Note they can cause problems if they are not run regulary so test it periodically


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## teemyob (Nov 22, 2005)

*Heater*

As tothers have suggested it is indeed a heater. It is an Eberspacher Diesel ADD Heater. It will currently only fire up with the Engine running.

Have on in our Current Mercedes and in our previous 416 I converted it to a Pre-Heater with timer. Also modified it to be a source of heating should we run low or out of gas when we Toured Norway (this was simply an ignition key with the Imobiliser removed).

The kit to convert it to a Heater with timer will cost for the part £150 ish.

This means you can set it to come on say 1 hour before you leave so that the interior is demisted and warm n cosy.

You can even buy a remote fob that allows you to turn it on from 500 meteres away or a Mobile Phone GSM unit and set it worldwide. But I think thats a bit OTT

Click the image below and you will see I installed the time clock with the Truma Boiler thermostat.

If you need any more info please ask.

Trev


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## trek (May 1, 2005)

Can not find a copy of your manual

but here is MB website with the latest sprinter owners handbook

http://www4-new.mercedes-benz.com/manual-trucks/ba/trucks/sprinter/en/index.html

it may be of some use ?


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