2002 sundance fridge not working on 12volt (1 Viewer)

Kyle123uk

Free Member
Aug 11, 2021
2
0
Funster No
83,374
MH
2002 swift sundance
Really struggling to get my fridge working on 12v. I have tested the engine bay 30amp relay, there is 14.4v going in to the relay with engine running and nothing coming out I have replaced the relay and still nothing. Any ideas where to look next? Alternator wires maybe?
Help appreciated
 
Sep 19, 2018
33
30
West Wales
Funster No
56,287
MH
Just looking
So what triggers the relay - ie how does a relay know the engine is running?
Sorry for the hijack.

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Apr 27, 2016
6,855
7,957
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
The relay has four wires. Two (the thin ones probably) will be the trigger (coil), labelled 85 and 86. These should have about 14V across them when the engine is running, and nothing when the engine is stopped.

The other two, probably thicker wires, will be the main contacts, labelled 30 and 87. One of these is the supply from the starter battery, and should be 12 to 14V all the time, whether the engine is running or not. There should be a fuse in this wire, near the starter battery, probably 20A.

The other contact, with the thicker wire, should be about 14V when the engine is running, and nothing when the engine is stopped. It goes to the fridge, to power the 12V element.
 
Last edited:
Upvote 0
Apr 27, 2016
6,855
7,957
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
So what triggers the relay - ie how does a relay know the engine is running?
The relay is usually triggered from the D+ signal, which the alternator gives out when the engine is running and the alternator is up to speed. It's the same signal that switches off the alternator warning light when the engine is has started.
 
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Kyle123uk

Free Member
Aug 11, 2021
2
0
Funster No
83,374
MH
2002 swift sundance
Thankyou auto router I have no volts through any other wires other than the feed from the battery. I will investigate the trigger wires today
 
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