speedometer not working

[Petemac]

IT WAS NOT A MERC FITTED RADIO THAT WAS IN IT JEST A OFF THE SHELF ONE IT HAD THE SAME PROBLEM WITH THE LAST OWNER THATS ALL I KNOW

 

[television]

I will see what I can find then, the diesels have different arrangements for the speed signal

 

[Petemac]

JEST HOME MALCOLM DID 40MLS DID IT 1TIME AT ABOUT 38MLS

 

[whitenemesis]

No need to SHOUT Pete!

 

[television]

It has to be something so simple a bad connection, electronic components do not normally fail in this way. You do have a connection block in the passenger side kick side panel, green and yellow wire that are there for taxi use.

I will look on the engine circuit to see where the output is taken from

 

[Petemac]

cheers malcolm sorry for shouting did not see caplocks were on

 

[television]

cheers malcolm sorry for shouting did not see caplocks were on

Thats OK my ears are very good

 

[television]

OK looking at all there is on this, the one common thing is the speed signal that terminates in the passenger side kick panel is the same green/yellow that drives the head,,,now either some of these multi connection block has a bad joint, or the cluster has a fault.

Now we know that if the wrong radio is fitted it can short out the speed signal, so is it possible that the last owner as been fiddling with the speedo head in the cluster. Now it should be possible to connect a multi meter to the speed signal using the ac volt scale, if the volt mater is reading when the speedo stops then we know the fault is in the cluster

 

[Petemac]

ok malcolm will try it 2moro willbe about 3 in the afternoon i will get back to you thanks peter

 

[Petemac]

good afternoon malcolm took kicker plate off i can see all the connectors there took a photo but cant download it my fault will i disconnect battery now and give them a good clean and look for poor contact the footwell is dry as a desert so no problem with water

 

[television]

If you have a volt meter, you can hook that up to the green and yellow wires and ground, in theory it should read out on the ac volt ranges, another thing when the speedo stop, give the top of the dash a thump to see it if reeds again

 

[Petemac]

so i do them one at a time and earth theblack meter cable will i disconnect the battery

 

[television]

Leave all the green yellows joined together, just put a meter lead on the join and the other meter lead to a good chassis point

 

[Petemac]

back to you in 2mins

 

[Petemac]

no readings good earth and i bridged the G/Y wire with bear copper wire

 

[television]

Maybe my thinking is wrong could it be DC,,, I though there was a RMS converter built into the speedo can you try it on DC it will be a very low reading,,,if not I will have to think again, I have never worked with Taxi meter and the like

 

[Petemac]

no reading again

 

[television]

If the speedo was working during this time I will have to try and re think on what that signal is

 

[Petemac]

can i disconnect the plug and check it clean it with the battery connected

 

[television]

If you mean the connector on the speedo then yes, but key out