Rectangular ceramic shunts/resistors
 

I've been searching for a couple hours and can't find an answer.

Does anyone know the resistance values for the different colors of resistors uses for the fuel and temp gauges? I've seen red, blue, brown, yellow.... But don't know the value to the color stands for. Thanks

Re: Rectangular ceramic shunts/resistors
 

I'm not sure what you are asking, but the resistance values for the gauge resistors are shown below.

Now, these resistors vary widely and they still work. Tom T-Bone is one of our gauge cluster builders, and he has more info if he see's this thread,

Attachment 1469052

The universal color chart for resistors is shown below, with the value of the color. The colors designate other values as well depending on their positions on the resistor.

Attachment 1469051

Re: Rectangular ceramic shunts/resistors
 

I was hoping you or Tom would have some insight. The ones I'm talking about are held down on the back of the gauges by nuts and washers. They aren't the kind you pictured. I'm trying to get my temp gauge to read a bit lower in the normal range than it does. It was normally reading at the highest hash mark for "Normal", not quite going past it to the "Hot" range. I've replaced the sender, tested the gauge per your suggestions on other threads and also put a resistor, like the ones you pictured above both in line with the sender (caused the gauge not to move at all) and across the two threaded gauge posts (also from a picture you posted from other threads). That is what I have right now and the gauge reads a little lower but still higher in the "Normal" zone. I requested pics of what others gauges read, but no replies. I'm pretty sure my flat, rectangular resistor is good but I'd still like to test it to know for sure.

Re: Rectangular ceramic shunts/resistors
 

Well I figured out that the gauge resistors are wire wound and have different colors per Toms thread on the gauges.


http://67-72chevytrucks.com/vboard/s...d.php?t=640615



I assume you have seen my posts on the temperature gauges where the resistors are added to lower the gauge readings, but I will add it here for the other viewers.


Attachment 1469119



And this




Attachment 1469118

Are you able to take an ohm reading on your sender when the engine is hot and when it is cold? Meter leads on the terminal connection and the engine block. Make sure the sender body reads zero ohms to the block as well. Some types of Teflon tape will give higher than normal readings on the gauge.

Is this the correct sender IOW you have not converted from a three gauge dash? And your engine is running at the correct temperature?

You can remove the resistor and measure the resistance with the meter for an accurate reading.

Re: Rectangular ceramic shunts/resistors
 

Yes, those are the pics I was referring to. And the resistors, the yellow one in the pic. Mine is blue but according to Tom's thread and research, the colors mean nothing so that answers that question.

With it wired like the first picture, the gauge rides at the very top of the "Normal" area, all the way to the last hash mark on the gauge before the "Hot" area. I ordered the exact resistors mentioned in Option 1 and first put one inline like Option 2 shows due to easier access and the gauge never moved. I figured the resistance was just too high to use it in line like that. I then installed it as Option 1 shows and I still have it like that. The gauge reads a little cooler but still on the higher side of the gauge.

My target is to have it roughly in the middle of the gauge. I'll check get those measurements either tonight or in the morning and report back. I'm fairly certain it's the right sender, it was ordered from a reputable online classic truck dealer that I'm sure we've all used and I did not use any type of Teflon tape or sealant of any kind. My cluster is an original gauge cluster with the only conversions being a tach and vacuum gauge that I added. In the process of adding those I put in a new printed circuit board, cluster pins and connector and an extra ground from the gauge tins to the dash framework. All of which works great thanks to you and Tom. I really appreciate the help.