Instrument cluster voltage limiter.

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J

jimmys67

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I have a 67 Valiant. My ammeter and temp gauges are not working. They did, until I pulled out the cluster to replace the dash bulbs. I must have done something, don't know what.
Is it possible that I shorted out the voltage limiter? I am still getting power at the temp gauge at the circuit board. The ammeter is stuck at 5/8 of scale. Won't move at all. The temp gauge is just buried at "C" I'm stuck. Please help. Thanks
 
The ammeter is not connected to the temp / fuel gauge. The IVR supplies power to both the temp and fuel gauges. There are several places for problems here

1.....The harness connector and the pins loose at the pc board. You must repair them. My board was so bad I abandoned the original connector and soldered pigtails to the PC board traces, brought them out, and hooked up "Molex" style connectors to replace them

2....The IVR itself, and the socket it fits into. On my 67, the brass contacts were not making contact between the contacts themselves and the board traces.

http://www.forabodiesonly.com/mopar/attachment.php?attachmentid=1714669336&stc=1&d=1383154832[img]

Consider buying a solid state RTE unit. There are projects on the www where you can construct a 5V regulator yourself to replace it

3....The gauge unit studs / nuts. They may not be making reliable contact with the PC board.

4....The guage units may not be accurate, or have something wrong, or even have debri, or "bugs" (insects) etc inside. You can check the calibration with resistors in substitute for the senders. The gauge units are identical so the resistors for checking are the same

The resistances are

L = 73.7 Ohms (empty)
M = 23.0 Ohms (1/2)
H = 10.2 Ohms (full)

For example, you can go to Radio Shack and buy four 100 ohm, 1/2 watt resistors, and wire all four in parallel. This gives you one 25 ohm resistor. Put this in substitute for the temp or fuel sender to ground, and leave the key in "run" for about one minute. If the system is working and accurate, the gauge should read 1/2 scale. (middle.)

5.....Grounding. Grounding is originally poor. Hook additional ground pigtail to the cluster, and bring it out and bolt to something such as the column support

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So far as the ammeter, I would inspect it for mechanical damage. These are a complete POS design. They are essentially held together by "luck" They are a piece of brass with two studs, and you may have "moved things" when you disconnected / reconnected the two wires. You may have knocked the needle off the pins

There's not much in there...........I don't know what model this one is (off the www) but it's just a needle on two simple pivots

[img]http://www.bradsnosparts.com/yahoo%20pics/120408%20001b.jpg
 
What you really want is 23, but 23 is not a standard resistor, and you want enough wattage that it doesn't heat up and change. They are cheap. A package of 4 is easy to get. Last time I was there they had nothing close to 23 ohms singally. Sorta like buying one egg.

You cannot look them up online, either. Radio Shack's idea of a "catalog" is "sort by price" or "best seller" How stupid is that.
 
For a little over $4, you can buy this resistor board on eBay and choose any resistance you need: [ame="http://www.ebay.com/itm/1R-9999999R-Seven-Decade-Programmable-Resistor-Board-Step-1R-1-4W-SKU9715A/371041895467?_trksid=p2050601.c100085.m2372&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140211132617%26meid%3D6158264365497835924%26pid%3D100085%26prg%3D20140211132617%26rk%3D3%26rkt%3D4%26sd%3D290959907836%26clkid%3D6158273023858282364&_qi=RTM1562571"]1R 9999999R Seven Decade Programmable Resistor Board Step 1R 1 4W SKU9715A | eBay[/ame]
 
OK before I seen your answer, I headed to radio shack. Asked for 4 100 ohm resisters, they did not have any. So I asked for a 25, he said I have a 22 ohm. So I got a pack of 4 for a buck 58, like cheep. I hooked one up turned on the key and the gauge went to a smidgit under 1/2. So all is well from the tank forward. Then I took my multi tester and checked the ohms at the sending unit with a full tank of gas. Well it said 73 ohms. So I am guessing sunk float.
 
I would say you are on the right track.

Now, in case 'you haven't heard' These "repop" senders have a real bad reputatin for being inaccurate. So if you can clean up and re use your old one you might be better off.
 
I am sure in my case it's the original 1964. Hoping that I can just fix or get a new float.
 
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