Does anyone know the location of the sensor that connects to the Temp gauge on dash. I have one wire to engine bay that has never been connected to anything. It has a ring terminal on it and comes from the gauge and protrudes the fire wall about 15 inches through the same grommet as the choke cable.

Have you discovered the use of the wire that has been discussed at great depth? It is one of the things that makes this "hobby" worth while, tell us where the wire was supposed to go and what happened to the capillary tube that originally "powered" the temperature gauge.
What a great "hobby" this is!!!!

Zoneman

What color is the wire?

Thanks so much for the advise everyone. Sorry I haven't answered, been away. The wire is blue with a yellow ring terminal. Definitely looks original

Am I right in thinking that the red/ yellow/ blue sleeves for amp ratings weren't in use back then? I think Volvo used black sleeves, and slightly longer ones at that. PV fuse boxes still used screw terminals. If this yellow terminal shows the crimp on the yellow part I'd say it was fairly modern.

Derek;

Color coding of insulator denotes wire gauge range of crimping ferrule (so indirectly correlates to current range), but this applies more for loose terminals used onezie, twozie, as a visual aid to the occasional installer. In a harness production environment, where crimps are fed from a roll into a pneumatic crimping tool, operators are less concerned about this...they make all crimps of a certain gauge , then move on to the next gauge. I think the black sleeving which is used on Volvo harnesses (which doesn't occur everywhere, was installed for mechanical strain relief in places where extra mechanical support was deemed necessary.

Cheers

Check to see if there is power on this wire, both with the key to the run position and with it to the off position. This may help you in identifying this "rogue" wire. Do all of your dash lights work? Aprox. what is the gauge of the wire? Good luck with your search!!

What color is the wire?

Hello,

The stock water temperature gauge is not electric.

The wire you describe might be for the oil light on the the dash and should be attached to the oil pressure sender in the back of the cylinder head if you car still has the B16 engine.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Thanks Eric, but the oil light works and is hooked up to the back of the block, and yes it is still a B16. Does the temp gauge need to be grounded? Maybe it's the ground wire. There is a plug right next to the oil pressure sender in the block. Is that normal? And where does the temp gauge get its signal from? I will try to load a picture if I can

To reiterate, the stock water temperature gauge for a 544 is not electric.

What you are probably seeing is the remnant of the capillary tube sticking through the firewall and not a wire.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Thanks for the input Eric, I will look a little deeper and get back

Vinr, the plug next to the 1/8" tapping for oil pressure is where the stock cap tube bulb for the temp. gauge was installed. There is supposed to be a very small shielded tube running from the bulb(where the plug is now)thru the firewall and into the dash mounted temperature gauge. If that tube is not present the gauge will not function. If this "wire" you talk about actually does go to the stock temp. gauge it can only be for the light in the gauge as the gauge was mechanically actuated.
Good luck with your project!!
zoneman

The oil pressure fitting is in the side of the block adjacent to the oil filter. The water temperature gauge sender is on top at the rear of the head. There maybe a drain tap for water on the side of the block close to the oil pressure switch. The water temp gauge is worked by the expansion of an alcohol based fluid in the tube from the sender. This is easily damaged if you're not careful when removing it from the head. The short length of metal tube must not be allowed to rotate when you undo the fitting into the head. If the tube breaks the fluid leaks out so the gauge will not work. Can be fixed but an expensive job.

Derek, your observations about the locations of the oil pressure and temp.sensors are correct for a B18 or B20, but not for a B16!!! I have one sitting less than 10 feet from me, I stand by what I said.
Have a nice Christmas!!
Zoneman

Yes you're absolutely right, I apologise for that. Did have a B16 Amazon in the '60's but only B18's since then. Sorry if I had people scratching their heads. I certainly wasn't in the zone!

Merry Christmas to you too and to all members of BB.