Eberspacher Problem

[si macc]

I've got some problems with an Eberspacher heater on an 88 Westy Joker, it has worked in the past.

The timer comes on fine but the heater does not switch on at all from the room thermostat. I've located all the fuses (4 of them I can see) in 2 fuse boxes. One of the fuses had blown, I replaced it and switched everything on and the light on the thermostat came on and I could hear the clicking of it getting started but then everything stops and the light slowly fades. Just to make sure I replaced the fuse and tried again and unsurprisingly it happened again. I haven't got the multimeter out yet to measure any voltages or properly traced the cable. From what I can see the cable that is causing the blown fuse is a thick red one, not sure if this info helps or not!

I will post more info as I discover it and some photos too. Any help/pointers as to what might be causing the problem would be greatly appreciated!

Si

[kevtherev]

http://www.club80-90.co.uk/pages/downloads.html" onclick="window.open(this.href);return false;

here will be a wiring diagram for an eber..hope it helps

[R0B]

could be a battery problem.is it fully charged?

[Oldiebut goodie]

could be a battery problem.is it fully charged?

Low battery blowing fuse? That's a new one.

It might help if you put up which model it is.

[kevtherev]

any grounded circuit will blow a fuse oldie.. even with less than 11V in the batt

[R0B]

did i say a low battery was blowing a fuse .its the other symptoms that sound like a low battery.the blown fuse could be a separate thing altogether.

[si macc]

any grounded circuit will blow a fuse oldie.. even with less than 11V in the batt

I thought this may be the case but at the fuse/battery end the circuit looks fine. Will check at the eber end tomorrow and get a new battery for my multimeter and get some readings up.

[si macc]

http://www.club80-90.co.uk/pages/downloads.html

here will be a wiring diagram for an eber..hope it helps

Got the wiring diagram, gonna take me a while to work out whats what i think!

Pretty sure its a D2L eber.

[Oldiebut goodie]

Sounds like the glow plug is shorted/ burnt out/melted or seized fan.
Does the fan spin freely before the fuse blows?
The thick red cable will be the main power for the heater which leads one to a high current draw problem, either as above or a direct short of that cable.
Have you the correct fuse inserted? It looks as though it should be a 16A for that model.

" by R0B » Thu May 21, 2009 9:28 pm
did i say a low battery was blowing a fuse .its the other symptoms that sound like a low battery.the blown fuse could be a separate thing altogether."
The lack of substance in your response leads one to the impression that this is your possible diagnosis for the two symptoms presented.
The only other symptom available for analysis is led slowly dying - which is usually residual energy in circuits discharging after the removal of power.ie after the fuse had blown.

" by kevtherev » Thu May 21, 2009 9:27 pm
any grounded circuit will blow a fuse oldie.. even with less than 11V in the batt"

Rob never mentioned a grounded circuit nor have I until this post, he only suggested a low battery and the recharging of! Why not respond to the OP with your helpful suggestion instead of throwing it into the mix at me?

[si macc]

Thanks oldie,

I will need to get more familiar with the eber end of the wiring. Will have a look this evening and report back. Got all the neccessary manuals/diagrams so shouldn't be a problem.

[si macc]

Just had a bit more poking around the eberspacher wiring. My multimeter is dead (needs new battery) so haven't been able to get any readings, plus run out of 5A fuses so can't replace the blown one.

All the wiring looks fine, no obvious shorts or corrosion. I checked the fuse on the Eber control box and it has a fuse T1.25/250V, its still intact so assuming this is the correct fuse. As someone mentioned before the cable that the fuse is connected to is coming from the heater. I have included a photo below of the fuse boxes behind the drivers seat, the fuse that is blowing is the right hand side fuse on the right hand fuse box. According to the wiring diagram for a D2L (if I have identified the right cable) goes to the 'PCB with room thermostat sensor' on the heater. Does anyone have any idea on how I can get to this? Does it involve dismantling the whole heater from the underside of the vehicle?

[Oldiebut goodie]

I can't work out what those fuses are protecting - according to the wiring diagram there is only the one fuse and that is a 16Amp at position 14. That cable looks far heftier than for anything that would be using a 5A fuse! Are you sure it shouldn't be 15A not 5A?
It looks as though you have a diy system of wiring there and you will have to trace the wiring to see what's what!

[si macc]

That's what I thought, it's making tracing cables very difficult! Gonna try write a wiring diagram for my van, find it easier to work out what's going on if I do that. Off to get a 9v battery for my multimeter so will be able to get some readings and trace some of the cables, think my mate has left his tools in my company van and pretty sure he's got a really good cable tracer so should come in useful!!

[si macc]

I have got the multimeter working and measure voltages at the control box end. Everything is reading around 12.5V so this looks ok. I managed to juggle around some fuses and found out that the left fuse in the right box doesn't affect the eber (I think!). The most important thing I found was when I replaced the blown fuse with another one I noticed I could switch on the fan from the thermostat and I could hear it running and feel it sucking in air but then when switching the heater on you hear click, click and then the fuse blows.

So it looks like a part of the heating circuit is causing the problems. I guess I will have to poke around the underside of the vehicle? Any ideas where to start and what to do when I get there?!

[Oldiebut goodie]

If it is definately the main fuse for the eber it will blow if it's only a 5A fuse without there being a fault anywhere. I would try the correct rating fuse before ripping it all apart first if I were you. If the glow plug is us or there is a direct short that fuse would blow also. You could check the heavy white wire from the control ( directly under the heavy red one in your picture)- check the resistance to earth - if it shows no resistance the glow plug is at fault.