jim fl4 Posted April 15, 2016 Share Posted April 15, 2016 Hi, before I investigate wondered if anyone might have experience with this fault. When ignition is off temp gauge needle is on cold, when ignition is ON needle flies up to max. Now, if this were an old car with an electric sender I would say its wire is simply running to earth, but in this case I don't know? I've looked and the braided cable to the thermometer looks fine? Thanks Jim Quote Link to comment Share on other sites More sharing options...
fv1609 Posted April 15, 2016 Share Posted April 15, 2016 Jim if it reads maximum it is open circuit somewhere. A likely place is the connector to the thermometer head or the wires inside. Quote Link to comment Share on other sites More sharing options...
jim fl4 Posted April 15, 2016 Author Share Posted April 15, 2016 Hi Clive, I will check that out tomorrow. Many thanks :-):-):-) Jim Quote Link to comment Share on other sites More sharing options...
fv1609 Posted April 15, 2016 Share Posted April 15, 2016 Jim be careful disconnecting the connector from the thermometer head as it is easy to find yourself undoing the connector internals. Also check that the screened cable rests above the distributor heat shield if the cable is under the heat shield it can get cooked by the exhaust manifolds. Also check the instrument panel end for the two cables to it are marked R1 NEG and R2 TEMP. The current flow through the circuit is about 40ma. The resistance of the thermometer is something like 180 ohms (depending on temperature!) I think. Quote Link to comment Share on other sites More sharing options...
jim fl4 Posted April 16, 2016 Author Share Posted April 16, 2016 Jim be careful disconnecting the connector from the thermometer head as it is easy to find yourself undoing the connector internals. Also check that the screened cable rests above the distributor heat shield if the cable is under the heat shield it can get cooked by the exhaust manifolds. Also check the instrument panel end for the two cables to it are marked R1 NEG and R2 TEMP. The current flow through the circuit is about 40ma. The resistance of the thermometer is something like 180 ohms (depending on temperature!) I think. Hi Clive, Had a look today and can report the following. 1. removed the connector to the thermostat, separated the two ends and checked - with ignition on needles flies up to max. 2. Clamped both ends together - result is the needle does NOT move. 3. reattached the wire ends into the sender, result needles flies up. Does this mean its the sender (thermometer)? Cheers Jim Quote Link to comment Share on other sites More sharing options...
fv1609 Posted April 16, 2016 Share Posted April 16, 2016 Jim I think your conclusion must be correct. #2 shows that there is integrity in the two leads. Can you just put a multimeter on ohms & put it in the sender to confirm it is open circuit but it does look that way. Check that the sockets in the sender are clean & not corroded. Quote Link to comment Share on other sites More sharing options...
jim fl4 Posted April 16, 2016 Author Share Posted April 16, 2016 Jim I think your conclusion must be correct. #2 shows that there is integrity in the two leads. Can you just put a multimeter on ohms & put it in the sender to confirm it is open circuit but it does look that way. Check that the sockets in the sender are clean & not corroded. Thanks Clive for your reply, I will try with the multimeter tomorrow and report back. Do you have any suggestions as to where to source a replacement sender...and headlight bulb :-)? cheers Jim Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted April 16, 2016 Share Posted April 16, 2016 Thanks Clive for your reply, I will try with the multimeter tomorrow and report back. Do you have any suggestions as to where to source a replacement sender...and headlight bulb :-)? cheers Jim Hi Jim, I will jump in here, I am sure Richard Banister has stock of these senders, 01797 253211, thought I saw some there on Friday. regards, Richard Quote Link to comment Share on other sites More sharing options...
fv1609 Posted April 16, 2016 Share Posted April 16, 2016 Headlight bulbs here: https://www.thexmod.com/item_detail.asp?id=3390 Sender is more difficult, thexmod have sold out: https://www.thexmod.com/item_detail.asp?id=8900 Bannisters may have one. http://www.milweb.net/go/banister/ Quote Link to comment Share on other sites More sharing options...
jim fl4 Posted April 16, 2016 Author Share Posted April 16, 2016 Hi Jim,I will jump in here, I am sure Richard Banister has stock of these senders, 01797 253211, thought I saw some there on Friday. regards, Richard Hi Richard, Thanks for jumping in :-):-), will test the sender tomorrow, its probably duff and then ring the above. Thanks for the lead :-). Cheers Jim Quote Link to comment Share on other sites More sharing options...
sexton Posted April 19, 2016 Share Posted April 19, 2016 I've found temp senders measure about 100 ohms at room temp. And I suggest confirming the R1-NEG wire coming out of the instrument panel is connected to ground, as well as the R1-NEG wire from the sensor. The wiring diagram shows this but I missed it and it had me scratching my head for a while. Malcolm Quote Link to comment Share on other sites More sharing options...
jim fl4 Posted April 21, 2016 Author Share Posted April 21, 2016 I've found temp senders measure about 100 ohms at room temp. And I suggest confirming the R1-NEG wire coming out of the instrument panel is connected to ground, as well as the R1-NEG wire from the sensor. The wiring diagram shows this but I missed it and it had me scratching my head for a while. Malcolm Thanks Malcolm, will do. Jim Quote Link to comment Share on other sites More sharing options...
jim fl4 Posted April 21, 2016 Author Share Posted April 21, 2016 Bannisters do them but at a hefty £110 plus vat I'm not rushing in. Anyone got a good 2nd hand one? Cheers] Quote Link to comment Share on other sites More sharing options...
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