If you have owned a Cougar long you know that the gauge readings are often not what you would expect. It is incredibly common to have the temp gauge reading hot when the car is actually not hot at all. Or fuel gauges that read perpetually low. Or oil pressure gauges that seem to be more mysterious than accurate. Aftermarket senders may or may not be supplying the right signal. The wiring in between can be suspect, and full of bad connections. And then gauges them selves need to be properly calibrated. It is hard to nail down the problem.
I have developed a gauge tester that will supply the right signals to allow you to test your gauges. You will unplug the wire to the sender and connect the tester to the wire on one end and to ground on the other (alligator clips make this easy). Switch on the High or Full position and the gauge will show a full tank, hot engine, or maximum oil pressure. Switch to the Medium position and your gauges should read right in the middle. Switch to Low or Empty and they should read the bottom of the scale.
I have built and tested prototypes and now I am in the tooling design stages for the housing and so on. It will be at least three months before they are ready. I hope to have it out there for less than $25. I will follow this with a sender tester to let you see what the signal is coming out of your sender.
But I have one more question. The gauges are all powered by the instrument voltage regulator putting out a nominal 5 volts. It is actually pulsed power so difficult measure with a gauge. What I can do is add a bulb that will show that the gauge is getting power. If you have a factory IVR it will pulse happily or if you have new solid state regulator it will glow continuously. It will add some cost. One the one hand if all the gauges are dead the instant answer is the regulator failed. If they work at all you don’t need to test this. On the other hand it is kind of nice to know that you don’t have a single dead gauge circuit. Is it worth maybe an extra $3 and a month in development to add this?
I would pay it. I have all my instrument cluster disassembled to restore it at the moment. Hopefully you will be done before I put it back together. The car I have didn’t run when I got it, hasn’t ran in 34 years, so I would like to test before I put back together. I can wait though.
Wow this would be an awesome tool to have! I think plenty of folks (me included) would happily pay that price for something like this. I would say the additional bulb would be worth the extra cost and development time.
The main cost of this thing is the tooling and minimum buys for all of the specialized parts. Maybe the light won’t cost much if it doesn’t have a huge buy in requirement and the tooling doesn’t change.
No need to take the dash apart. You just unplug the wire from the sender, use the attached alligator clip lead to connect to the end of the harness you just unplugged. The other clip lead goes to ground.
This will also test the low fuel relay circuit as well.
It might work on an '88. I do know it works up to about '83 but I didn’t check much past that. I need the specifications for the gauges to tell for sure.
Interesting. I presume it will work with a circuit card installed on the dash (69 on up) where the power input leads from the IVR are all hooked up together for oil, temp, and fuel gauges.
A common problem on 69/70 gauges is when you replace a circuit card and the actual gauges move a bit around such that any one of the posts touches the metal dash cluster. You can’t see the contact happen because the gauge posts are buried under an insulating pad, the circuit card, and the nut that tightens everything down. When the sending line post touches ground, the gauge won’t register; when the input power post touches, all 3 gauges won’t register.
Of course, the ammeters have their own circuitry and are very hard to test with the dash cluster installed.
Some great feedback here. That issue with the '69 sounds challenging. Good thing we have you sorting those out. I do think this will also cover all the early Mustangs as well. Testing ammeters is a whole nother issue. I have only seen a couple that actually worked.
