The mystery conversion accessory control boxes with relays and fuses. Circuit diagrams and information.

jaahn

Active member
Hi :)
These control boxes are fitted to ambos and buses that are modified in Australia by various conversion companies. They seem to use some designs that continued to be used over some years. As the original manufacturers have now gone or been taken over the information of what they do and how they work is hard to find. I thought it might be useful to put some information on here for a reference. I was helping Huski find a problem with his ex-ambo and he found some CrispAir information and a circuit diagram in his ex ambo van glove box. Please feel free to supply any information you have, that might be useful to other owners.:cool: It would be helpful if the year and model was included to identify the van.

I have a 2000 312D long wheel base bus. It was originally bought as part of a large fleet for the Sydney Olympic games for disabled transport and then sold. Many have been converted to campers. Some were also 313 models I believe. Mine has an aftermarket dual air conditioner fitted by CrispAir and a Quicki side step. It also had a wheel chair lifter.
The air conditioner is controlled by the original Merc switches for the dash outlets but the rear high outlets have an auxiliary switch unit on the dash. The compressor is supplied and fitted by CrispAir and the condenser is under the drivers side of the van with three electric fans and there is a control box fitted to the passenger seat base with quite a few fuses and relays all labeled in the circuit diagram as clearly the a/c . So if you had a failure, then looking at the Merc wiring diagrams would not be useful As you can see there are fuses in the control box.

My control box below looks to have a circuit board that is similar to the circuit diagram that Huski found. Labeled made by Emergency Light and Sound, Manufactured by Impart Special Products. Part no ELS 103F Code 0200jb. Control box Sprinter , 12V. The circuit diagram is a slightly later update, 2003.
Jaahn
crispair bus box 2 passenger seat base.jpgcrispair bus box 3 circuit board.jpgCrispAir diag2 IMG20201123181918.jpgCrispAir diag1 IMG20201123181916.jpg
 
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jaahn

Active member
Hi :)
The model that Huski owns. Van is a 2006 build Sprinter, 2007 conversion for ambo - with front and rear air conditioning - all using the one compressor by Crispair. Ex Vic ambo.
The air con control box has not been located yet, any suggestions as it seems to have a possible blown fuse for the a/c clutch after the compressor was replaced but no fuse labeled air conditioner clutch found yet and no board similar to the circuit diagram he found(like mine above).

The control box for the other ambo accessories is the one shown below and the circuit diagram inside the cover. Again lots of relays and fuses and some electronics. Circuit EA45BPB2 Relay Control. Mader MAS/RAV Sprinter 2003 . issue 6. 30/5/2006
It shows the lists of the accessories and the fuses and relays.
Jaahn
Mader ambo control box  external.jpg Mader ambo control box circuit board.jpgMader ambo control board circuit diagram 1.jpgMader ambo control board circuit diag 1 rotated.jpg
 
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Eric Experience

Well-known member
Jaahn.
I had the same, I found it ridiculously complex and pulled the whole lot out. If you keep the aircon you will soon realize that is not very useful, but if you are determined to use it you can make it operate with with just two relays. Eric.
 

jaahn

Active member
Hi :)
Here is a copy of the Owners Manual for a Sprinter Dual Air Conditioner possibly from about a 2004 model bus. It had a circuit diagram the same as the first picture WSME 8604 rev 00 30/08/03.
Eric I have found my air conditioner quite satisfactory and have no intention of removing any parts of it. While it may be a complex control system it is robust and well made with fuses etc. I have had no problems with any of that and having found the information I put here I can trouble shoot it if necessary.
Jaahn
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jaahn

Active member
Hi ;)
Following up on this thread after another year For Huski's van, a 2006 build Sprinter, 2007 conversion for ambo - with front and rear air conditioning - all using the one compressor by Crispair. Ex Vic ambo. I have some pics taken at the time when I looked at it and found the 'lost circuit board' which was located under the drivers seat mounted flat above the other electrical relays and stuff. Almost not visable until you remove the seat.:rolleyes:
The Crisp Air air con is controlled by this board and it does have standard type relays for each control circuit and each one has a standard blade fuse and these are easily seen and replaced if you are looking at the correct board. The dash control unit links to this main board with the flat ribbon cable. Picture one is the main control board. M103G-A3, A very robust made unit IMHO.
The circuit diagram was printed on the cover and is shown, in two identical pictures, one rotated for ease of reading the item descriptions. The last is a pic under the seat at the other electrical relays etc, :ROFLMAO:
Good luck if you find this thread in the future as it could be your salvation !
Jaahn
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owner

Oz '03 316CDI LWB ex-Ambo Patient Transport
I had the same crispair dual evaporator one compressor in my 2003.

It has two solenoid valves that switch between the front and rear, aka time division multiplexing in computer engineering terms.

The trouble is these valavs get weak with heat, and they start acting a bit like a TXV valve. So they start cooling your engine bay lol.

I eventually removed the rear circuit and valves and just ran it front only on mine for many years until the compressor died. The big old skool Denso conpressor they use is very expensive to replace

So I changed to the actual German stock setup. This comes on T1N vans equiped with climate control from the factory. Pretty rare in Oz since they usually just fitted a crappy crisp air type AC locally even if you ordered a van with AC new at the dealer.

The German setup has everything but the TXV and evaporator different. So the compressor, condensor, hard lines, soft lines and receiver had to come from the doner. Plus the bracket mounting the compressor to the block. The German one is also Denso but smaller and with only 3 mounting points rather than 4 of the crisp air.

This setup provides way more cooling than the crisp air setup. Considering I'm still using the same TXV and evaporator etc. And my German setup is also secondhand. The difference is night and day. And the German compressor is a lot cheaper new if its ever needed.

BTW im still using the crisp air wiring, but its a mess. I plan to simplify the wiring at some stage like Eric suggested.
 

phiblack

Member
2004 model is under the drivers seat. Just took the seat off, then the fibreboard protector and the control box was under that. Exactly same as the image at the top of the page. They don't make it easy. Took me an hour to locate it. Thanksfully no blown fuses.
 

phiblack

Member
Jaahn.
I had the same, I found it ridiculously complex and pulled the whole lot out. If you keep the aircon you will soon realize that is not very useful, but if you are determined to use it you can make it operate with with just two relays. Eric.
Hi Eric,
Can you share details re using two relays only??

Phil
 

owner

Oz '03 316CDI LWB ex-Ambo Patient Transport
I believe In Oz these never (or very very rarely) came with the factory AC setup even when ordered new with AC. They arrived with nothing but the stock evaporator, and the rest of the system was either installed by dealers locally (aka subbed out to their local aircon place), or was fitted by the ambo fitout turkeys (or their subbies) if it was an ambo.

So its just a basic on-off type AC system and any local AC workshop (or good DIYer) can wire it up with 2 relays and a switch.

The factory system like they got in the USA is a lot more complicated with cabin sensors and ECU control etc. It would be prohibitively expensive to try to create that setup.
 

phiblack

Member
I believe In Oz these never (or very very rarely) came with the factory AC setup even when ordered new with AC. They arrived with nothing but the stock evaporator, and the rest of the system was either installed by dealers locally (aka subbed out to their local aircon place), or was fitted by the ambo fitout turkeys (or their subbies) if it was an ambo.

So its just a basic on-off type AC system and any local AC workshop (or good DIYer) can wire it up with 2 relays and a switch.

The factory system like they got in the USA is a lot more complicated with cabin sensors and ECU control etc. It would be prohibitively expensive to try to create that setup.
Thanks OWNER. I will speak with my local AC guy. My wife says we don't need AC but I am hating that I at leasy don't have it there to turn on off as I want. The simple system seems great. I will see if I can find some guides online as to how to wire it up.
 

owner

Oz '03 316CDI LWB ex-Ambo Patient Transport
This one runs the aux fan as temperature controlled, manual controlled, or via the AC. It replicates what the stock setup does, plus adds manual mode. All you need is a relay, a switch and some wire. But in practice you would want a 2nd relay and switch for the AC clutch side of it. Mine also runs an additional wire to the lowest speed pole on the dash blower fan when the AC is switched on.

You could go even simpler than this, just search for trinary switch AC circuit.

 
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