calibraiting temp gauge?

ddw350

Registered User
after i broke my old temp sending unit,i got a new one.the old unit was all corroded,but read well on the gauge,it did show cooler than normal,but the fan came on at exactly on "m" on the gauge.to my surprise,the new unit goes well past "m" like 2-3 letters if it had them.so i tried to calibraite[is that how you spell that?] by using resistors from radio shack.friend of mine told me years ago chrysler had a tech bullenton on their gauges flipping out,going way past where they should.they actually suggested using resistors to fix the problem.my s10 did that and the right resistor fixed it. i ended up buying a 99 cent pack of 15ohm-1/2 watt-5%tolerance and 10 ohm.the 15 hardly moved the needle off the blue[at operating temps] the 10 ohm let the needle move between the "n" and the blue.it seems to need a 5 ohm or 2.5 to make it closer.i,ll be returning the 15 ohm and i,ll see if they have the others.let me tell you,it gives you piece of mind not seeing the needle over near the red before the fan comes on! thought you guys might find this interesting
 
i have the same problem with my temp gage. but i'm not seeing any signs that the engine is really overheating either. how can you tell by adding that resistor if the gage is displaying correctly? do you calibrate the meter by when the fan comes on at 220 degrees?
 
i put round quick connects on either end of the resistor,then stick one end on the sending unit post,the other end in the wire that hooks to the sending unit.it doesnt do anyting to change when the fan comes on,just allows the needle to move less than normal.when the unit in my s10 failed,i replaced it,and the gauge was still alll messed up.the resistor worked well.of course the s10 has a gauge with #s on it so i used the infrared heat gun to check temps at the therm housing and tried a couple of resistors till i found the right one.radio shack does not sell a 5 or 2.5 ohm resistor.of course thats what i seem to need to get the needle where it should be on the gauge.
 
you can take (2) 10 ohm resistors and tie them together in parallel to make a 5 ohm, or tie 4 of them to make a 2.5 ohm. Problem solved. Hooking two identical resistors together in parallel cuts the resistance in half- always worked for me for many years.
 
i'll be damed....i rememberd something of that nature from school[13yrs ago],but the guy at radio shack didnt say anything about it when i mentioned it to him......i,ll try that after my new problem is fixed..brake trouble...
 
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