The Classic Machinery Network

Good day,

I recently bought old JCB 3CX 4x4 sitemaster 1987 white cab for work on house construction.
Unfortunately lights are not working and I have problem to find diagrams and manuals for this type of dash with bullet fuses.

I would like to ask you, If someone here have similar machine and can share with me wiring diagram?
Here in download section are only manuals and diagrams for different dash with blade type fuses.

Thank you!

Hi and welcome Agrimax may be able to help you out. Your machine has the continental style fuses; I would carefully take each one out and clean the contact where it fits and replace each fuse, that is always a good start.

Jeremy

Crikey where has the time gone! A 1987 now 32 years old. Some thing that old when I was an early school boy would have been built in the 30s and probably deemed almost useless. The 87 JCB can do everything the latest one can do albeit slightly slower and lest comfortable.

I'd start with a spray bottle filled with water and a small drop of mild dishwashing liquid to wash your fuse block (dust can be good insulator).

I had a look at the circuit in the closest manual I could find:
JCB 3CX/4CX Backhoe Loader workshop manual

This shows different serial ranges having very different fuse functions, but fitting fuses to sockets 1 & 2 will tell you something.

My guess would be that those two fuses are missing because of a fault, but give it a go.

Hello thank you for your tips, I cleaned fuse box and replace fuses.

Fuse 5 always burn out, in the diagrams I see that nubmer 5 is connected with turn indicator lights which Also do not work.
Also horn is not working which is on same fuse and fuel gauge is powered but shows always empty.

gecko.cx wrote:I'd start with a spray bottle filled with water and a small drop of mild dishwashing liquid to wash your fuse block (dust can be good insulator).

I had a look at the circuit in the closest manual I could find:
JCB 3CX/4CX Backhoe Loader workshop manual

This shows different serial ranges having very different fuse functions, but fitting fuses to sockets 1 & 2 will tell you something.

My guess would be that those two fuses are missing because of a fault, but give it a go.

gecko.cx, thank you very much for your tip!
In this manual I found wiring diagram with 8 fuses and it seems to be the very similar.



I also attacehd picture of my dash from behind, there is visible area which seems to be damaged, may be it is the cause of not working turn indicators.
there are also two relay flashers which has only two pins but in diagrams on pos. 57 and 59 should have more connection than two.

In the diagram, 57 and 59 are not the flashers but the lights. The flashers are 32 and 33, and have indeed only two connections.

The damaged PCB could indeed be a part of your problems, but if I had to guess I would think that this kind of damage was more likely to be the result than cause of the fuse blowing. And not a normal result of course, but might happen if someone got impatient and replaced the fuse with something more substantial, like a bolt.

Does the hazard flasher work, or at least not blow a fuse (fuse 3 according to the diagram)? If so, I would think that the flasher circuit was less likely to be your chief problem, and if it is, it would be in the part of it between the fuse box and hazard switch.

There are, according to the diagram, two other circuits powered off fuse 5. The horn and something called a "bucket reset solenoid" (number 42 on the diagram). Either of these could be the cause of the fuse blowing.

--
Regards, Kári.

Bargud wrote:Fuse 5 always burn out,

before you run out of spare fuses, a trick I find helpful while testing is to pull a few strands out of some speaker cable (or other light wire).
Just check the width of the original fuse element and use a strand or two to give 1/4 the width (you want it to blow at a fraction of the circuit rating).

Hi, I have a 82 3cx white cab with the bmc engine. The wiring diagram seems the same as my digger. Does anyone know the ratings of the fuses from 1-8 please?

gecko.cx wrote:

Bargud wrote:Fuse 5 always burn out,

before you run out of spare fuses, a trick I find helpful while testing is to pull a few strands out of some speaker cable (or other light wire).
Just check the width of the original fuse element and use a strand or two to give 1/4 the width (you want it to blow at a fraction of the circuit rating).

For blade type fuses, you can buy sets of fuses with pop out breakers, the circuit goes overloaded, the button pops out. You reset by pressing it back in. Great for diagnostics and cheap.

https://www.ebay.com/itm/373719747394

The op is on torpedo fuses though, which don't appear to come in reset-able ones, if anyone knows better though I'd be really interested to hear from where though you could probably make a one off bastard offspring of a blade reset fuse and a torpedo holder for testing.

MrF wrote:The op is on torpedo fuses though,

Ooops - missed that.

Not a fan of those ceramic fuses haveing replaced one without fixing the problem.
... lined the fuse up and pressed it in with my thumb.
The smell of burning flesh and the pain arrived at the same time as the fuse element glowed red while I was still pressing it in..

Can't say I recommend the process.