More wiring oddities…

Not much happening this week due to work pressures and music projects going on. The weather hasn’t been great following a mini heatwave although I’ve had the odd hour here and there after tea, painting / rubbing down the lower dash. I’m not at all happy with the finish on this but it will have to do for now. Just waiting for some parts to arrive from Craddocks before I can reassemble and fit it and do a final write-up.

This evening at 7pm it suddenly stopped raining and the sun came out so I thought I’d have an hour outside. This meant missing ‘The Archers’ but I like to live on the edge sometimes, unpredictable, dangerous, yes, that’s me…

As mentioned before, the wiring on this vehicle is a puzzle and a worry, a potential fire even.

One thing that had bugged me was the fact that the electric cooling fan was on permanently once the ignition was switched on. These things draw quite a current and after reading about the 200tdi engine generally running too cool, I thought I’d investigate. Of course nothing is as simple as it looks, especially where wires magically change colour where they pass an obstacle. This is due to previous owners mending or modifying with any bit of wire that may have been available, normally a piece of mains flex!

I thought that maybe the thermostat unit was short circuit but a quick check with the multimeter discounted this theory. So I started tracing wires and drew a diagram. I stared at it thinking I had traced a wire wrong so repeated the process. It turns out that the relay switch contacts had been completely bypassed. This wasn’t a case of a connector falling off and being connected wrong accidentally, the crimp terminals had been connected this way.

I sketched out how I thought it should go, referring to another (wrong) diagram I’d found on a forum, connected it up and started the engine, no fan. As it was getting a bit late to be running a noisy, smelly diesel close to houses I didn’t wait for the temperature to come up, but just shorted out the thermostat with pliers to test the relay, success, the fan came on. I will adjust the thermostat another day.

For reference if anyone needs a working diagram:

Capillary thermostat placement

This electrical fault got me looking at the thermostat and I found that the actual bulb is fitted into the drain plug at the bottom of the radiator. No doubt this is a special fitting but the thing feels incredibly loose as if it’s held in with a soft thin rubber. I’m not happy with this arrangement so I have ordered a blank drain plug to replace it (hopefully correct – I believe the radiator in my vehicle is one for a Discovery but I’m not actually sure) and will find a more secure method of fitting the thermostat, probably into the hose itself. I will do this when I fit the new heater matrix as I will replace the coolant then.

Bad earths everywhere

Every earthing point I have seen on this vehicle, without exception, is extremely dodgy looking – rusty screws into corroded aluminium. I will formulate a better solution and will investigate fitting some earth blocks where I need them and run cables from those to the main earth.

New fusebox required – any advice gratefully received

I am also planning on fitting a more modern ‘blade’ type fusebox with many more circuits, it’s just deciding on where best to fit one. I was amazed to discover that the lights and other circuits aren’t fused at all. I quite like the idea of fitting one inside the seat box but it will have to be done in such a way that the seat box can be removed easily. Leave a comment if you have any ideas on this!