big click when orange light goes out now absent - no start

[Auntie-Freda]

Been away for two weeks and on return the Bongo won't start. The engine turns but no way is it going to start. The big click I used to hear when the orange light goes out is absent. I assume that the click is a relay which is now not functioning? Its not the 10A fuse in the dash - that ok. The battery is good and fully charged. Any ideas on how I might fix it...? Thanks

[Auntie-Freda]

I have done some more investigation and when I turn the key I get 5.5 volt across he rail for a few seconds and then 0 volt after the light goes out. The big click I normally hear when the light goes out is audible but much more muted than normal even with everything open. The glowplugs where replaced last year and the van has been starting fine upto this point. The battery might have been running a bit low recently due to frequent short trips but is charged now. The battery was new last year and cranks the engine no problem so I'm pretty sure its not the battery. Any ideas.

[g8dhe]

Well two possibilities given the low voltage your measuring on the Glow Plug Bus (GBP) and assuming that the battery is fully charged;
1. There is some resistance between the S/B and the GBP, which could be from the relay or the fuse connections (in-line fuse just behind battery).
2. The GBP is drawing an excess of current possibly the bus is partially shorting to the chassis, occurs sometimes after changing the glow plugs.

Its probably fairly easy to check for shorts first, and then if that doesn't show any problems try seeing if you can connect your meter to measure the voltage between the fuse and the relay, if the voltage is low there that would point at perhaps corrosion in the fuse, if its a full 12 volts then unplug and check the relay connections.

B2-04 is the Glow Plug relay several possible positions for it but all in the same general area;

[Auntie-Freda]

I found the relay bolted to the side but cannot locate an in line fuse behind the battery anywhere - is there always one there. Its too dark to check for shorts. The area around the relay was pretty damp almost like it had been leaking. I took the relay off but there was no sign of corrosion on the connectors. Is it possible to test the relay on the bench. Its too dark to test for shorts now and Im not sure how to do that anyway. do I just check 12v at the connectors working away from the battery?

[francophile1947]

but cannot locate an in line fuse behind the battery anywhere

It's not an in-line fuse, it's a fusible link which, if memory serves me correctly, looks like a thicker "hairy" wire

[g8dhe]

I found the relay bolted to the side but cannot locate an in line fuse behind the battery anywhere - is there always one there. Its too dark to check for shorts. The area around the relay was pretty damp almost like it had been leaking. I took the relay off but there was no sign of corrosion on the connectors. Is it possible to test the relay on the bench. Its too dark to test for shorts now and Im not sure how to do that anyway. do I just check 12v at the connectors working away from the battery?

Yes there will be one, its actually a fusible link rather than a standard in-line fuse, but the ones I've seen look similar to an in-line fuse, there maybe more than one type of construction of course !
Yes its basically a case of working down the wires to find out where the voltage is being dropped, the circuit is here;

The fusible link comes directly after the battery (1.25sq GLOW) is wired across to the relay (B2-04), from the relay it is wired down to the Glow Plug Bus (B2-06), with a connection off to the ECU, the fact that you can hear the relay clicking and that volts appear on the Bus means the relay coil is OK, but it could be the relay contacts inside (the covers will normally prise off to check) the relay wiring contacts (you've checked) the fuse or the termination on to the GPB itself. The most common problem is a shorting bus bar, followed by relay contacts, after that it varies or is something else know one thought of! You have checked the battery voltage when the glow Plug light is lit, and its not just a case of a good battery but not having sufficient charge in it to run the plugs as they draw something like 16 Amps I think you will find?