another-user

ive got a 69/350 and the temp gauge/wiring is all stock.

my issue is that it seems to be reading low. its been doing this for the last season or two now, and iive finally decided to get around to sorting it out.

ive followed willcox guide on testing, and everything has passed. ive put a new thermostat in, and a new temp sending unit.

under normal driving conditions, it reads on the high side of the 100 notch. when its "hot" itll reach the 1/4 mark, as soon as i start getting some air moving, the temp drops right back off. so it appears the gauges are working, but theres a calibration issue someplace?

i havnt worried about it too much, its just time to get it fixed. ever since i had my radiator cleaned, and put in all the new baffles for it, i knocked off an easy 30-40 degrees under full load.

carriljc

go to the Willcox website and order the Temp Gauge adjustment contraption they sell. Worked great to tweak my temp gauge to read correctly. Easy too.

https://willcoxcorvette.com/corvette...resistor-68-76

my installation story:
https://www.corvetteforum.com/forums...-question.html

0Willcox Corvette

At some point, someone has probably changed the sender. All aftermarket senders fail... (it's very rare to get one that reads correctly even in the so called "Exact" reproductions).

The adjustable resistor should cure your issues... this is exactly why we made them

Willcox

another-user

looking at the video, im wondering if my resistor just went bad?

its an original one, and the temp gauge has worked fine for the previous 10 years ive had the car. but when i pulled the gauge cluster apart to clean and repaint, thats when i first started having an issue.

0Willcox Corvette

Checking the old resistor is easy.. remove it from the gauge and test it for ohms from one side to the other.. While 90 is the given standard, it can deviate from around 85-92 ohms.

Willcox

another-user

so im not sure if the resistor is bad, or my el cheapo multimeter is bad. the resistor reads as low as 87.9, but the multimeter shows spikes all over up to 150ohms. kinda leaning towards a busted resistor?

0Willcox Corvette

I'd question the meter... the resistance should be aprox. 90 ohms with the resistor disconnected from the gauge.

another-user

i just cleaned both ends of the resistor and measured it on my desk (wood) its in the 88ohm range (saw as high as .9 and as low as .3)

so, assuming the resistor is good, what should i look for next?

i know my gauge is moving, but its barely coming above the big 100* mark under normal operation, and 3/4-ish way to the 180* when its hot.

as soon as they car starts moving when its hot, i can watch the needle drop back down to that 100* mark.

before i cleaned the radiator and put the baffles back in, i used to see it go to the right of 210* on occasion. and before i cleaned my gauge cluster, i saw it hover around 180* mark. its only been since i reassembled everything that the issue has cropped up.

carriljc

here, go do this testing. Should help you determine issue:
http://repairs.willcoxcorvette.com/1...erature-gauge/

0Willcox Corvette

Testing a 68-76 Temperature Gauge -or- What your non working gauge can tell you!

'75

Has the needle been off the gauge Maybe it just needs to be reset to a known point on the gauge with a certain resistance.

another-user

i just put the resistor back in, and i had the opposite problem. it wouldnt stop climbing. after about 2 mins it was past 210*. and i know it wasnt that hot.

i just pulled the my entire cluster out this afternoon. ill look into it and get some pics up of what im looking at.

another-user

i dont know if it means anything, but my seat belt warning light doesnt work anymore either. not sure what happened there.

another-user

i dont know if it means anything, but my seat belt warning light doesnt work anymore either. not sure what happened there.


found the issue with the no seat belt warning light. blown gauge cluster fuse. now riddle me this... why did my battery/gas/ temp gauge(kinda) work, when the gauge cluster fuse was blown?

not that any of this solves the tamp gauge reading incorrectly still.

0Willcox Corvette

What is all the silver foil stuff on the back of the housing? Is this possibly touching something?

If the gauge is working properly, you should be able to remove the ohms wire and it show as it does in the video. If you ground out the ohms wire it should do the same as the video posted above. If it works this way then your gauge is probably fine. If it doesn't then you have a gauge issue. Each of the test below should read exactly how it is pictured... any variance would mean you have a gauge issue. Lets say you ground out the ohms wire and the needle is at 4 o'clock... then there is an issue. Either the needle has moved or the gauge is toast.



Find a known source for your ohms input.. Or take a couple of flashers, take an ohms reading off of them in a series. Typically it's around 50 ohms so if you use two of these you'll be around 100 ohms input..

Put 12 volts on the gauge power terminal, ground on ground and put the flasher in line. With 100 ohms input the gauge should go to right around the first mark. (aprox).

Or (the smartest thing for testing gauges) you could just purchase an adjustable pot online... set the reading to 79 ohms... the gauge should read 210 degrees... This will tell you if the gauge is working properly and if it goes to some other reading then remove the needle, set the pot to 79 ohms and re-set the needle.




Or..........................

You could just send the gauge to me and I'll put it on the tester. If you wish to do this email me at Support@Willcoxcorvette.com

another-user

got it going. it was the aluminum tape i used when i upgraded to LED light strips in the housing (needed a good reflective backing to get some bright, readable gauges in the car finally). turned out one of the studs was touching the tape.

now, next question. do you carry the ammeter condensers that go on the back of the gauge cluster? i cant find them on the site. the wire fell out of mine when i was putting things back together today...

0Willcox Corvette

Just answered your email..

carriljc

I would get rid of that metallic tape. If you need better light reflection, then you can just paint (I used white paint for mine)..... all that metallic tape can only create future problems as it unpeels and whatnot.
As far as that condensor(capacitor) - I just purchased a standard ignition condensor(capacitor), and (for the condensor behind my tach) I soldered on the old connector so I could plug it right into the harness.