Problem with my cooling fan not cutting in on CB42 993cc HIJET

Can anyone help me read this wiring diagram its like spagetti. I have a problem with my cooling fan not cutting in on CB42 993CC HIJET. I have tried to follow the wiring from the 20 A ENGINE FUSE to the motor which is fine but it looks as if it goes through the rear wiper and washer switch this is where it gets confusing.I have bridged my fan switch wires when engine is up to "NOT" and it works fine but just need to know what enables the fan to work just the temp sensing fan switch in rad or a signal from the engine temp sensor to fan switch? bla bal bla......If its just fan switch then ill just replace that.

Before checking the wiring check the bottom hose is hot. Airlocks occur there, no water = no fan = shagged engine.

Cheers. Yes Iv just replaced the cylinder head gasket. I will make sure its well bled up. The bottom pipe was hot. Is the wiring quite simple and just 12v in and ground out and does the fan switch just short to earth once it gets to fan run temp @ about 85 deg.Many thanks

It is the fan switch in the bottom of the rad although I had wired a switch in as a bypass as the switch I had did not work so I could keep using it and at the MOT it suddenly started working again which came as a suprise but I digress if you bridge it at the connector and the terminals are clean then it is the switch there is no relay.

Did I speak to you on the phone earlier?



Most of the time on a Hijet which the fan does not kick in - if you touch the bottom of the radiator its still cool - yet the temp gauge is off the scale.

Yes I have done the head gasket run the vehicle up and it started bubbling and gurgling and water was overflowing from the header tank.My sudden thought was shite is the head gone again but didn't get into the red so I hope not so I removed the fan switch and furry twat and tested them both I put the thermostat in water of about 85 deg and didn't open until it reached about 90 deg and it said 82 deg on the stat also put rad switch in water of 90 deg and tested continuity with multi meter and nothing so I thing both are funked so hopefully this will explain boiling of water because initially I didn't use coolant.So to sum this up I'm going to replace fan switch and furytwat and hopefully get to the bottom of my overheating prob.If anyone has an idea of the reading in ohms I should get from the fan switch this would be good.TBC

I have finaly sorted my van . There was alot of rusty water in system so I decided to double Flush it got it up to temp without the thermostat in them drained it twice.I replaced the thermostat and fan switch and the fan wasn't working so I took it round the block making sure I got it up to a good temp and still didn't kick in it was dangerously getting close to the red .I checked hoses and they were all hot but I persisted and one thing I done was drive it back and forward several times this seemed to work and once left standing for a few minutes with hot fans on it kicked on I believe I had a slight air lock and sticky new stat .Another trick is leave the heater valve open for water to flow through matrix and use 80% coolant glycol

80% is too much and will cause hotter running.

Yep, glycol is actually a poorer coolant than water due to its lower heat capacity.

50/50 is the strongest mix to use which will protect you down to minus 15 or something.

Ok thanks for that will drain some out