instrument cluster issues

[steveh]

Having the following issues with 69 dart non-rallye dash.

1) Speedometer needle bounces at low speed.

2) Gas guage is dead

3) Dash lights dont illuminate right turn indicator comes on solid when
headlights are on

Temp and Amp gauges work. Voltage limiter is good (test light pulsed when connected to the temp sensor wire). Suspect it is a grounding issue in the dash and or tank since all the other gauges seem to work. Thoughts and ideas on where to trouble shoot first?

Many thanks
in advance

 

[BillGrissom]

The speedometer is mechanical. When the needle pulses it is because the spinning magnet shaft is worn in the bore. I sent the magnet assembly to a speedo shop in Bakersfield and they put a bushing in the bore. That was ~1992 and its still working fine.

The running lights are probably a filament in the same bulb as the turn signals. I don't think the two circuits interact anywhere else (other than grounding), but you should check a wiring diagram (can find on FABO or web). Perhaps one of your turn signal bulbs is installed wrong or the socket or wiring is shorted.

A bad gas gage is usually because the copper float in the sender (tank) doesn't float. Hard to access, so check electrically first - measure resistance of sender, substitute a resistor for the sender. You can find values w/ searching. Something like 8 ohm full and 70 ohms empty (or vice-versa). If you don't have a multi-meter, $3 on sale regularly at Harbor Freight.

 

[67Dart273]

Sometimes a bouncy speedo is NOT the speedo but a cable problem. I dare say more often than NOT it's a cable problem

There are several areas of concern.

ONE The connector pins on the instrument PC boards. These get corroded/ break/ loose

TWO The grounding screws which attach the PC boards to the casting. These get corroded, and or the casting itself may not be grounded.

THREE The nuts on the back of the gauges may not be making contact with the PC boards. loosey/ tighty the nuts several times back and forth.

"Quick check" your gauges by shorting the sender lead to ground. Turn on the key and watch for the gauge to head quickly for the right.

 

[RedFish]

The bouncing speedo needle most likely is the cable and sheathe.
The dead fuel gauge is most likely the sender in the tank.
Easy test... open the trunk and find the wire goung through the trunk floor to the sender. Shove a shirt pin in that wire then use a jumper with aligator clips to ground the shirt pin. Turn ignition switch on, fuel gauge needle should travel swift and smooth to its max position. If it does the problem is under the car, Could be the ground jumper over the rubber fuel line at the sender or the sender itself.
Turn indicator in dash comes on with park lamps is definately a fault or loss of chassis ground at that front park/turn fixture. This is a common problem with any make or model where the front fixtures are part of a plastic grille.

 

[steveh]

Thanks all for the assistance with troubleshooting this. Got started today but didn't get very far before I realized I have a bigger issue at the bulkhead connection. Here's what happened...

Pulled the cluster cleaned all the pins and terminals, carefully scoured the contacts on the PCB to ensure good connections at the gauges and grounds.

Tested the gas gauge (less than a second with DC) needle moved so its not fried. Put it all back together then had absolutely nothing at the dash. Had current all the way to the bulkhead but nothing under the dash

So I Pulled the center bulk head connector. Male terminal was barely sticking out...slight tug and it broke. Part of the plastic surrounding the female terminal is missing so it is now loose

Tried using a standard male terminal (not packard 56 series) but it was too loose. Arced bad once and melted the insulation on the hot wire.

1) Any quick fixes out there that won't start a fire. Can I just pull the loose female terminal through the connector wire it to the hot lead outside the bulkhead connector?

2) As for a more permanent fix...does anyone make/sell the bulkhead connectors or do I have to by a complete harness.

thx in advance
Steve

 

[RedFish]

NAPA stores sell the terminals. There should be unused ports in that connector.
I suspect you do have a short circuit somewhere though.

 

[steveh]

Thx redfish...that makes sense didn't even think about going through an empty port in the connector. just read an excellent article at MadElecrical.com that provides a step by step fix for this issue. Link is here for others to see.




They also sell a wiring upgrade that looks pretty decent. Anybody ever use it. I don't know sqwat but it looks like it would fix much of the muscle car era wiring problems (dim lights, etc) without the high cost of new harnesses. Mine dart and cuda aren't showcars , but I do need a dependable electrical system and this looks like a good choice, low buck alternative (as compared to a new harness).

thx again to all, I'll continue to post my progress ask questions etc as I go along. Who knows...with any luck, today I may actually get to do what I intended to do in the first place which is fix my speedo and get the gas gauge sending unit fixed.

 

[RedFish]

Most of us have seen the Madelectrical pages before.
It works for some, where age and moisture were the only causes for failure.
For others there are more issues than deleting the amp gauge and bulkhead connections.
Remember the connection fails at the weakest link.
If you send more current to the ignition switch then try to pull more current through it...it becomes the weakest link.

 

[steveh]

ok...found the 56 series terminals at NAPA hooked everything up through one of the empty ports on the bulk head. After monkeying around to get a good tight connection through the old bulkhead everything checked out fine...had juice under the dash. So I hooked everything back up and as soon as I reconnected the negative terminal on the battery, it arced and the wire going into the bulkhead melted again. UGH!!!! Went back and wired in (butt connectors) a 14 gauge fusible link which uses AMC fuses so I can continue to trouble shoot without melting wires or burning out more bulkhead ports.

So thats where I am...Car has to sit for a couple days while I go to Nashville to get my boys (been at granny and papas for 4 weeks). Hoping to spark some decent dialogue on what this could be....I'll kick it off by highlighting what I did that lead to this issue.

While troubleshooting the cluster for a inop fuel gauge...
1) I took everything apart cleaned the PCB, terminals, grounds etc.
2) Wiped gauge surfaces and reinstalled them.
3) Left the speedo cable unhooked.
4) Replaced a bad 10amp fuse in the far left slot of the fuse box that controls the dash lights.

That's it...ever since then every time I reconnect the instr cluster and put the neg term back on the battery, I get a Zap at the bulkhead that is frying the fuse in the fusible link I installed.

Was mad as hell at first, but quickly realized just how lucky I really am even though I don't know squat...the 69 dart GT convertible may have electrical issues, but in the end I still drove home from the garage in a 67 formula S...I've got no right to be upset.
"It not about having what you want but wanting what you got."


As always thanks in advance
Have a great week-end
Steve

 

[RedFish]

Fault appeared before or after the ignition switch was turned on ?
Before is amp gauge, or headlight switch wiring related. After is gauge limiter, fure box feed related.

 

[steveh]

fault appeared before the ignition switch was turned on. Fusible link going into the bulkhead started smoking as soon as I put the negative wire back on the battery.

Amp gauge and Voltage limiter were both functioning before I pulled the cluster. When I put everything back together, I noticed two abnormalities (perhaps)

1) the bottom nut and washer on the amp gauge studs began to turn as I tightened the the top nut which holds the ring terminals in place. It wasn't sloppy or anything but I was afraid to overtighten them for fear of damaging the PCB

2) Both studs on the amp gauge had washers then the lower nut. When I removed the amp gauge, the positive side washer came off with the nut. The washer on the positive side appeared fixed to the PCB. Didn't try to pry it off (again afraid of damaging the PCB). Of all three gauges, only the ground stud of the amp gauge had a washer that appeared fixed to the PCB...didn't think nothing of it at the time...but now I'm second guessing everything.

 

[67Dart273]

When you get back, put the largest 12V lamp you can dig up IN SERIES with the battery ground lead. This will prevent the short from damaging stuff while you look for it. A stop / tail lamp with the two filaments wired in parallel is good, an old (working) headlamp is even better

 

[Inertia]

You may want to temporarily install a 20 or 30 amp breaker, while you search for the ground.(short).. you can feel the heat in the harness up to where short is.. Mac also make a similar tool.. saves a lot of time, and money, and frustration..

 

[steveh]

Yep...put in a 30 amp breaker just before the bulkhead so I wouldn't melt another port on the bulkhead.

So even if the breaker fuse is getting blown, the trouble spot in the dash harness will still become warm??? just making sure I understand

 

[67Dart273]

No he's talkin temporarily. Same as putting a lamp in there as I suggested. Different folks make a "short finder" that's what it IS --a breaker and a compass. You put the breaker in the main lead, and the short causes the breaker to cycle. You move the compass around on the harness, and it deflects with the large magnetic field caused by the short:

[ame="http://www.amazon.com/Tool-Aid-SGT25100-Short-Finder/dp/B002XMUGZC"]Amazon.com: Tool Aid (SGT25100) Short Finder: Home Improvement[/ame]