fuel gauge and temperature sensor not working

[mk2 transit crew]

Hi All,

i have done all the checks i can think of.

my engine is a 2.5di fitted in a mk2 that's being rebuilt after refurb hence having to connect everything up.

engine originally had a plastic thermostat housing with a twin wire sensor. didnt work when the other wire of the sensor was earthed. found out thermostat wasn't working not that it makes any difference. Changed thermostat housing to a metal one and fitted new single wire sensor white ring. (not sure which one it should have) still doesn't work.

put the temp sensor in boiling water, still nothing.

earthed both live wires of the fuel and temp gauge. The dials work. If the dials work at this point does it mean that the voltage regulator in the clocks is working??

fuel sender is new also.

put spare set of clocks in. dont know if they work or not they are just spare. still nothing changes.

any ideas what could be wrong or further test to do?

on a side note the heater matrix appears internally etc in good nick, both pipes to it are very hot but also dont get any heat into cab.

any help would be gratefully received.

[mk2 transit crew]

Hi All,

After doing even more checking online i now understand how a it works.

the voltage regulator behind the dash speedo cluster controls the fuel gauge and coolant sensor. if working correctly on a transit mk2 it should reduce voltage from whatever the battery is on ie 12v plus down to 5v. This is to ensure that the gauges read accurate. as if the gauges were not reduced to a static constant voltage then then would be inaccurate due to the fluctuation in battery state.

so i tested the voltage and found 5v on each cable supplying the fuel gauge and coolant sensor. If i had found no voltage at all and the gauges where showing nothing then this would mean the voltage regulator is likely faulty if all the cables are in good order etc.

I tested that there was resistance on both fuel gauge and coolant sensor. of which there was so this proves a circuit is present.

My findings was i put around 7l of fuel in the tank as im still working on modifications to the filler neck. it wasn't enough hence showing nothing. Even after 15l total it only starts to register on the fuel gauge. presumably once i fully fill the tank it should show full which i will find out soon.

Regards the coolant gauge i had a spare sensor so heated it up with a flame and the gauge moved so this is also working.

i have fitted a mk4 or mk5 radiator as they are cheap and easily available. i think my issue might be its cooling very well and potentially too well as i believe the radiator is slightly bigger with more cores. also potentially i have the wrong coolant sensor so will have to research which one is correct for the engine.

Hope this helps anyone in the future

[Neil]

yes voltage regulator on the back of the clocks

[Neil]

yes voltage regulator on the back of the clocks

[JIM T]

Hi there not posted for ages but had this problem on my mk2 Hymermobile did everything as in other post but no joy new sender ,new ,voltage regulator after checking the wire from sender to clocks I found a high resistance so a change the wire from sender and also changed all spade connections but still no joy .
Then I had a look at the fuse box in the dash it seemed ok but took all of them out and cleaned and replaced all fuse bingo that sorted the charging light being on even after fittings a new alternator ,fuel gauge working now but no temp gauge yet .I may put another set of clocks I have to see if its the gauge ,I will keep you informed if this works ,keep sucking air and you’ll be ok JimrT.