# Hymer B644 Electrics



## 123574 (May 16, 2009)

Sorry I appear to have put my post in the wrong box!

So my 1999 B644 has developed an electrical problem that seems to have started after hitting some rough roads. The control panel alternator over the door shows a 10A approx discharge when driving but goes to 0A when the engine is off! Sometimes it acts properly and shows the expected charge form the alternator - the alternator warning light on the dash goes out as expected when starting the engine .

Any thoughts where to look?


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## vicdicdoc (May 14, 2005)

OK, this sound familiar . . last year I kept getting the same readings of discharge - I finally traced the problem to the 30amp blade fuse in the engine compartment - its the fuse from the alternator, mine looked ok but putting the multimeter across it resulted in no reading.
Also check the blade fuse holder - mine was partially burnt out where the fuse was arcing across the fuse holder - a new fuse holder & [good make - not chinese crap] fuse cured my problem . . hope it cures yours - let us know


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## 123574 (May 16, 2009)

will do many thanks


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## 123574 (May 16, 2009)

This has been a while as had to have rear brakes sorted to get MOT so could not look at electrics. 

Anyway had a close look at that 30A fuse ( in a loose fuse block by the baterry ) and sure enough it was badly scorched and melted so after checking all others I replaced it and charging etc all seemd ok.

Having worked on car electrics in a past life I wanted to know what was causing the burning - so find the Electroblok ( on passenger side in cabinet) I could see that the circuit board was looking decidedly dodgy with what looks like white marks across it and powdered solder the result of - I suspect - spilt drinks - Why did Hymer put in such a place where the passneger is likely to place drink cans and the like? To go on I pulled the Electroblok out and took the top cover off and then carefully removed the circuit board ( the one with all the fuses ) gave it a gentle clean with a dry cloth and then with some electronic spray cleaner, put it all back together and touch wood all seems to be working as it should!

Thanks again for the tip to look at the 30A fuse.


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## vicdicdoc (May 14, 2005)

Just glad you found the prob & got it sorted ok.
I'm a clever boy, I'm a clever boy :lol: [makes a change] !


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