My '66 Hardtop Town Build

[jopizz]

It don't think it matters which way the gauges are hooked up. I would make sure you have power to the CVR first.

John

[Cwcb08]

It don't think it matters which way the gauges are hooked up. I would make sure you have power to the CVR first.

John

havent checked yet ( might be 2moro now ) but the oil temp gauge works so that means the cvr has power right?

[jopizz]

Yes, if your oil gauge is working then your CVR is putting out voltage. If you put a test light on the wires at the temp and fuel sender it should pulse showing that voltage is going through the gauges. At least it does with the mechanical CVR.

John

[simplyconnected]

The CVR has a male and female connector so it's impossible to hook it up wrong...

John is right and I've been here before. When I build my CVRs I install a fat diode on the power leg just in case someone connects the BATTERY backwards. Don't laugh, I know one guy with a '55 whose battery was backward for years. He only realized when he installed a new battery.

Mechanical CVRs pulse (hence the reason '66 'bird has a choke on the CVR). Mine output a solid and steady (regulated) six volts. This prevents the possibility of burning a gauge out because the mechanical contacts stuck shut, sending constant 12-volts to six volt gauges.

havent checked yet ( might be 2moro now ) but the oil temp gauge works so that means the cvr has power right?

All gauges powered by the CVR are connected in parallel so they operate independently.

Get that volt meter going, Cody. It will tell you what's really happening. Gauges are not polarity sensitive meaning, you can connect the power wire to either post. They don't have a 'motor' inside but they do have a bi-metal strip with ni-chrome wire wrapped around it to create variable heat from variable current produced by the sending unit. The needle is connected to the bi-metal strip. - Dave

[Cwcb08]

No reading on my digital multimeter from the temp sender lead grounded to the battery or from the fuel sender lead to the good ground in the trunk. Only place I got a reading was the low fuel light lead. Didn't have the car running but key was foreword. All fuses are good in the panel.

[jopizz]

I would start at the main connector that goes through the firewall. Disconnect it and make sure all the contacts look good and nothing is burnt. If everything is good there then it's most likely your fuel and temp gauges since you say that your oil gauge works.

John

[Cwcb08]

I would start at the main connector that goes through the firewall. Disconnect it and make sure all the contacts look good and nothing is burnt. If everything is good there then it's most likely your fuel and temp gauges since you say that your oil gauge works.

John

The temp guage did "work" ( when grounded see here http://squarebirds.org/vbulletin/sho...16&postcount=1 ) not sure what changed as it stopped "working" before i pulled the gauges out
I've never seen the fuel guage move.

might have to pull the main plug

Can you get to the back of the gauges without pulling the cluster out? When I had the face off I noticed two screws down there

[Cwcb08]

ok so i went out to the garage when i put kiddo down for a nap.

removed all three gauges



turned the ignition on
6v at the oil guage, 0 fuel, 0 temp



so now i need to decide how I'm going to fix this. easy or hard way.

hard: pull the stupid dash out again and find where the wires are busted. - really don't like this idea even tho its probably the right thing to do.
easy: make a daisy chain with male/ female connectors to take the good 6v and split it between the 3 gauges and abandon the other two wires in place ( tape off the ends so they cant touch anything and cause problems)




tested the gauges while i was there





also made a little test light with a bulb and some leads i had left over from a relay installs

[Yadkin]

Nice that you can reach the terminals from the front- I was not able to do that.

If you look at the wiring diagram all three of the "hot" wires from the CVR are spliced together in the harness. So "chaining" them together like you suggested isn't a bad idea at all.

[Cwcb08]

Nice that you can reach the terminals from the front- I was not able to do that.

i would be able to pull them further but i put coloured zip ties on them when disassembling so i could keep them straight easier

If you look at the wiring diagram all three of the "hot" wires from the CVR are spliced together in the harness. So "chaining" them together like you suggested isn't a bad idea at all.

right, pretty sure thats what I'm going to do, just won't be factory is all

[simplyconnected]

Good for you, Cody! You finally busted your meter out. (My Fluke measured 5.98 but I'm sure my leads had some resistance.) I also love the test light you made. It may look very dim on six volts but that's ok. It's a 'visual' for you to actually see how much voltage there is (or isn't).

As a caution... Make sure you disconnect your battery until you are done connecting your new wire harness. Too many loose ends that are hard to keep track of can short to ground. I use spade terminals that are insulated, both male and female. Had I known, I would have included some with the bullet terminals I sent.

You're doing great! Keep up the good work. - Dave

[Cwcb08]

Good for you, Cody! You finally busted your meter out. pretty easy once i found some time to do it!(My Fluke measured 5.98 but I'm sure my leads had some resistance.) I also love the test light you made. It may look very dim on six volts but that's ok. It's a 'visual' for you to actually see how much voltage there is (or isn't).

As a caution... Make sure you disconnect your battery until you are done connecting your new wire harness. Too many loose ends that are hard to keep track of can short to ground. I use spade terminals that are insulated, both male and female. Had I known, I would have included some with the bullet terminals I sent. fortunatly i have a handful of m/f insulated terminals i bought when i did my little horn button relocate so i will be using them when i build the harness, possibly 2moro but you know how days off go when the "boss" has plans

You're doing great! Keep up the good work. - Dave

as always i appreciate the words of wisdom guys

[Cwcb08]

What's wrong with these two photos...




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The wires are both hot!

I'm 99.9% sure I didn't mess it up because I removed wires and marked them one at a time so I could reassemble it the same way


After fishing the wires Back and into the other gauges

Bingo!



Strange that when the engine temp went up the fuel gauge went down?



I'll start it again 2moro after it cools off and see what happens, if it does that again

[simplyconnected]

There's nothing wrong with both pictures.
If the sending unit is not connected to one side of the gauge, the path is not complete to ground so both sides of your gauge will be hot. Now, you come along with a voltage tester that IS tied to ground so rightfully it will read the same voltage on both gauge terminals. There is no load, not even the meter because it is too sensitive.

Resistors (sending units ARE resistors) work the same way. If there is no load (no current flow), voltage will measure exactly the same on both sides of that resistor. That's why it's important to use a test light, because the bulb causes current to flow. The test bulb is a load which causes the resistor to oppose or resist current flow.

Your gauges have nothing to do with each other in their operation.

Lesson (in reverse): Let's say you have a circuit that keeps blowing fuses because a branch wire is shorted to the body somewhere, but we don't know where. If you attach the test light leads across the empty fuse holder, the light would shine until you remove the short. That's because the circuit is already shorted to ground. Simply start unplugging harnesses until the light goes out. Usually, wires and lamp holders that are exposed to the outside fail first because of corrosion or damage, so start there. Pay attention to the history... If the problem happened just after setting the dash, look for a pinched wire under a bolt or between sheet metal, and so on...

So in this exercise the bulb itself IS the resistor and it limits current from frying wires. If you put your meter across the bulb while it's shining you would see a voltage drop. With the ground removed, the bulb would go dark but voltage on both sides of the bulb would measure exactly the same, hot on both sides. If you have questions, fire away. - Dave

[Cwcb08]

There's nothing wrong with both pictures.

Well maybe "wrong" wasn't the right word. Between the six wires 3 should be hot ( 6v from the cvr ) 1 hot at each guage. Well I had 2 hot from the cvr at the fuel guage.

I figured this out by grounding one side of my meter to the body and probing the connectors while I was trying to decide what wires came from the sending units and what I was going to abandon when I made my new harness from the good 6v at the oil guage.

Anyway one more issue mostly solved, once the new wheel cylinders come in this week and I install them I think I'll be ready to take it down and get a "pre safety" to find out what else ( hopefully nothing ) it needs to be put on the road!