#149406  by dannello
 Fri Mar 01, 2019 10:02 am
I have a Toyoace 1986 factory made Motorhome. Beside the fuse box under the seat there is a blue LUCAS box with several wires. I traced one of the heavy duty wires from this unit to a 20amp fuse but no current is present. I think the wire goes to the fridge, the fridge does not work on 12v. Can anyone tell me what this Lucas box does? My web search suggests it is a relay of some sort. You can see the wire on the left of the box the connection is coloured yellow on a red wire and this wire goes to the fuse box shown in the background, it is also a red wire with yellow connection at the right hand side of fuse box. What do all the other wires do, is there wire diagram somewhere?
 #149407  by zl1dt
 Fri Mar 01, 2019 10:24 am
Could be connected so that the 12 volts only gets to the fridge when your engine is running. You would drain your battery fast with out charging input.
 #149408  by mattn
 Fri Mar 01, 2019 11:03 am
I would say so - a gas/12V fridge on 12V will flatten a typical starter battery in 5-8 hours. The 12V is really only designed to keep the fridge cold when driving.

The easiest way to check the fridge is working is use a multimeter. Check the relay is working correctly and switching on when the engine runs. Turn the engine off and measure the resistance of the fridge circuit - turn the fridge to 12V it should measure around 1-2ohm, turn the fridge off 12V and it should go open circuit.

(Repco have multi meters less 30% at the moment, so around $15 for a cheap one.)
 #149432  by vansvilla
 Fri Mar 01, 2019 7:37 pm
It's an aftermarket fit so no wiring diagram will exist.
 #149434  by BUSRSQ
 Fri Mar 01, 2019 7:46 pm
vansvilla wrote:
Fri Mar 01, 2019 7:37 pm
It's an aftermarket fit so no wiring diagram will exist.
Damn it beat me to it :)
Yeah could be for anything, has been fitted by one of the previous owners.
Not even a very good Job TBH
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