I know this is in the wrong forum but I know it will probably get the most views here so here goes...I installed an Autometer mechanical water temp gauge today and it doesn't want to work. It lights up but the gauge itself does not measure temp. I used the clock wiring harness for the 12v ignition power source for the light on the gauge and the gauge sender 12v source. I used the ground from the clock harness to ground the light on the gauge and grounded the gauge itself on the thermostat ground as the instuctions say to use a ground close to the temp sender for whatever reason. It lights up BUT does not read temp. Any ideas???? Perhaps a better ground for the gauge. Please help!!!
THanks

 

More then likely you dont have any water flowing over it so its not reading anything. If its mech. then more then likely its the big bullbus sender one thats huge compared to the electrical one. You have to put it where water is going to flow over it. The only way that I know of to get the sender that is that big to have water over it is to put a T in on of the larger coolant lines to the rad. Most people put a T in the top hose that comes from the head.

 

I teed a line in the heater hose so it's seeing coolant flow. Anyone else??

 

A mechanical water guage does not require power or ground to work (that's why it's mechanical).It is either broken or not seeing temperature.

 

Thats where you are wrong. The temp sender needs a ground and a 12v source to operate.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr.Death &raquo;</TD></TR><TR><TD CLASS="quote">Thats where you are wrong. The temp sender needs a ground and a 12v source to operate. </TD></TR></TABLE>

Negative. Go park your car in the sunlight on a hot day. I was suprised to see that my temps under the hood would rise up to about 150-160 on the gauge. And yes it did move. It dropped to 120 after I parked the car in the morning and then by lunch it was 140ish and then by 4:00pm it was 160. So no it does not need power to work.

Soo if it does, then I wouldn't mind having an explaination how it mysteriously moved haha. Perhaps you're thinking of the electrical gauge because then yes that would be correct.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr.Death &raquo;</TD></TR><TR><TD CLASS="quote">Thats where you are wrong. The temp sender needs a ground and a 12v source to operate. </TD></TR></TABLE>

Then it's an electrical water temp guage.I've built plenty of race cars with no electrical systems at all (magneto ignition) and the guages worked just fine.

 

Sorry it's an electrical gauge. Here are some pics.
Back of gauge.

The light uses a 12v power and a ground which I tapped into at the clock wiring harness. The other 3 wires are a ground which I attached to the thermostat ground, a 12v wire which goes to the clock harness(same as gauge light..o.k. or no??) and the last wire goes to the terminal post on the sender.
A pic of the sender which I tapped into the heater hose which is always open so coolant flow is always present. Where did I go wrong??

 

You are missing a wire in this picture. Because you have the sender mounted in rubber hose like that, which is how I have mine, you must run a ground wire from the sender to ametal surface. If that is your ground wire then you don't have the sender wire hooked up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1158 &raquo;</TD></TR><TR><TD CLASS="quote">

You are missing a wire in this picture. Because you have the sender mounted in rubber hose like that, which is how I have mine, you must run a ground wire from the sender to ametal surface. If that is your ground wire then you don't have the sender wire hooked up. </TD></TR></TABLE>

bingo, all the senders need to be grounded

 

You guys were right. It seems that the copper that the sender was attached to needed to be grounded. At first I tried grounding the sender itself and the gauge went all of the way to the right and stayed there so then I tried grounding the copper "T" and presto it works. Here's a pic to further explain what I mean. Thank you Honda Tech....

 

Glad it worked. I had the exact same problem. I even had a ground wire attached to the t fitting. But it wasn't good enough, I think the sealant I used on the threads was not letting the sender see the proper ground.