how to test instrument cluster gauges?

[resq302]

Hello,

I am having a problem with trying to get my gauges to work in my dads 70 chally.  I tried grounding the sending unit wire to see if the gauges moved with no luck.  I know the voltage to the gauges are supposed to be 5 volts and not the 12 volts that the rest of the car is.  The gauges that do not work are the fuel gauge and coolant temp gauge.  The alternator gauge works fine.  Is there a way to test them out of the car as I currently have the instrument cluster removed since I had to repair the speedometer also.  Any way to test the voltage limiter outside of the car also?  I am considering changing the stock style limiter to a solid state one for more reliablilty and acuracy of the gauges (when I get them working).

Thanks,

Brian

[Back N Black]

Here is a test for the Voltage limiter.

Voltage limiters can be tested out of the car with a few jumper wires and a test light.
Hold the limiter with the terminals facing you.
The horizontal terminal should be on the top. The vertical terminal in the middle and the angled one on the bottom

Ground the horizontal terminal. Supply 12v to the vertical terminal.
Touch a 12v test light to the angled terminal. You should get a pulsating light on the test light.
If the light doesn't flash or stays on all the time the limiter is bad.

The limiter does not provide 5v. It provides a pulsating 12v that averages out to 5v.

[Back N Black]

This was posted eariler by Plumcrazy.


Chrysler made a tool for checking guage calibration. It's basicly a can with two wire leads attached to it with a three position rotary switch that selects one of three resistance values.

The LOW position is 73 ohms
The MIDDLE position is 23 ohms
The HIGH position is 10 ohms

Temperature guage (a little vague)
The L position should read "C" plus or minus 1/8th inch
The M position should read in the driving range left of the 1/2 position on the dial.
The H position should read "H" on the dial.

Oil guage (also a little vague)
The L position should read "L" plus or minus 1/8th inch.
The M position should read 1/2 on the dial
The H position should read "H" on the dial

Fuel guage (better)
The L position should read empty plus 1/32nd or minus 3/32nds
The M position should read 1/2 on the dial
The H position should read full plus 3/32nds or minus 1/32nd

[six-tee-nine]

Read this,


I know, it's alot but i'm sure it's worth the effort.

[BROCK]

Read this,


I know, it's alot but i'm sure it's worth the effort.

I'm not seeing a link

[Plumcrazy]

If you want to test just the individual gauges, connect a 9 volt battery to the terminals.  Just don't peg the gauge.

Also look real close at the circuit board, the pins lose contact sometimes with the printed circuits which will take out a gauge or two.

[resq302]

Again, this is not for my 69 Charger but for my mom and dads 70 CHALLENGER.  They have a totally different set up with no board on the back or pins at all.  Each gauge has its own wire going to the back of it on the cluster.  The voltage limiter is also a slightly different design and not a push in style but one that has wires that clip onto it.  I rebuilt the voltage limiter today with a solid state internal upgrade so no more slow repsonse gauges.  It now has a constant 5 volts which is more reliable also.

I was able to have dad help me with holding two D cell batteries together giving me 3 volts and held wires to each of the ends of the batteries and tested the gauges that were out of the car.  The good news is that they went up about half to 3/4 of the way which should be correct since 5 volts would be full or all the way to the right.  With any luck, tomorrow, everything will be back in and I can take it for a spin before the weather gets crappy (and too hot.....supposed to be 96 tomorrow w/ t-storms).

Thanks for everyones responses.  At least dad will not run out of gas now...... welll... hopefully!

[resq302]

Ok, I was able to change out the gauges and got everything working except for the fuel gauge.  I think that is still not working because there is no ground jump strap from the sending unit to the hard fuel line.

Thanks again for everyones help.  At least mom and dad now have a working coolant temp gauge.

[Ghoste]

Yep, definitely need those ground straps.

[six-tee-nine]

Read this,


I know, it's alot but i'm sure it's worth the effort.

I'm not seeing a link

Yeah damn, something went wrong (probably me)...
Well here ya go

http://www.dodgecharger.com/forum/index.php/topic,37999.0.html

[resq302]

Ok, the fuel gauge is now working again.  Between the missing ground strap and the float barrel being filled with gas, it is finally fixed.

Thanks for everyones ideas and help.

[Sixtyeight]

Here is a test for the Voltage limiter.

Voltage limiters can be tested out of the car with a few jumper wires and a test light.
Hold the limiter with the terminals facing you.
The horizontal terminal should be on the top. The vertical terminal in the middle and the angled one on the bottom

Ground the horizontal terminal. Supply 12v to the vertical terminal.
Touch a 12v test light to the angled terminal. You should get a pulsating light on the test light.
If the light doesn't flash or stays on all the time the limiter is bad.

The limiter does not provide 5v. It provides a pulsating 12v that averages out to 5v.

Hi,

I have tested several limiters this way, I have limiters that pulsate very fast, some very slow and some very irregular. Which ones are good, or best to use?

Jeroen.

[Nacho-RT74]

every one got its own pulse. All depends of the points opening according with the heating element and coil specs and mostly sure there is not two twins on this

IMHO would go with the faster one as posible, which provides a more constant and "steady" source