Grounding issue started with the horn.....

[smitty040]

My 67 Dart's horns have not worked since I picked it up. Yesterday I decided to tackle the issue. I cut a few lengths of wire to use as jumpers/grounding and removed the switch off of the firewall. Good news is positive wire to both horns shows they work. I at first thought that maybe it was a bad relay or horn switch in the wheel. Disconnected the ground and used a jumper wire to the fender for a ground and got nothing. Used the jumper wire on the block for ground and got nothing. Jumped the two positive terminals and horns sounded. Ok easy enough, its a bad switch. Got a new one from Napa hooked it all up and still nothing. For some reason I thought to take a jumper wire from the ground terminal on the switch to the negative battery post and the horns sounded on both the new relay and the old. I am concerned that I have a grounding issue with the car. I have the slant in it and have not been able to locate a grounding strap for the motor. I see the one for the trans. The car has no dash lights, no high beam indicator when on, no fuel gauge, and no temp gauge. The headlights, tail lights, turn signals, and flashers all work. Any thoughts???

 

[67Dart273]

I think you are using incorrect terminology, and this makes it difficult to follow what you are doing

Switch? Do you mean "relay?"

HOW THIS works. The horn relay does not need a ground. It has THREE terminals, battery, horn, and horn button or switch

When you GROUND the horn button wire, this should operate the relay and sound the horns

The no1 trouble with horns is usually the "button" itself, that is, the switch in the column or horn ring. You can easily get "right down" to it by consulting a wiring diagram, and grounding the horn wire right at the column connector

You can download FREE service manuals at MyMopar as well as simplified wiring diagrams from there

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So far as a 'grounding strap' if the engine is not CONNECTED to the battery by means of the main battery ground cable, then it would never crank. The issue is usually a poor ground from battery (or engine) to the body. A good way to do this is to use a "ring to ring" starter cable, you can buy in different lengths, go from block bolt near the rear to the body with a substantial bolt, or bolt to one of the master cylinder mounting studs.

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Dash grounding is usually a separate issue. Run a separate ground pigtail from a ground point on the cluster that you can bolt to the column support. So far as dash lights, the tail lights MUST work FIRST. The dash lights are "a bit of" a trick

The headlight switch section that runs the dash lights gets power from the tail circuit. So in order for the "inst" (instrument) fuse to have power you must

Have a working tail light circuit

Headlight switch must be in park or head

Dimmer control must be twisted to left.

At this point, output FROM the dimmer control goes TO the instrument fuse, fed by a tan wire..............through the fuse...........and out to dash lights

 

[smitty040]

Yes the relay is what i was refering to when saying "switch".

I've unscrewed the center cap on the wheel and can see the black horn button wire. I disconnected it and ran a jump wire to the ground i am using for my external temp gauge and got nothing. I've tried to remove the ring to inspect and clean but the screws are impossible to get out. the one i did get out looks like it pulled the plastic out with it where it attaches to the beauty ring. Are the horn rings readily available for the '67 before i do any more damage?

As for the dash lights. All of the light circuits work. ive pulled the headlight switch out and turned it all the way to the left right before the click for the dome light. when i use the turn signals they light up on the dash as well as when i use the flasher.

The cluster grounding issue. Would that cause the dash lights not to work? Where is the best grounding point on the cluster?

Im not sure about the regulator if it works properly or not which i heard can cause problems with the gauges but if the cluster is not grounded i assuming the regulator would not work anyways?

I have the wiring diagrams from the factory service manual. I get the basic path of the wire just didnt want to tear into harnesses before i did all of the easy stuff first. Thanks for the help so far.

 

[67Dart273]

There are several problems that can cause grief in these clusters.

1....Loose or broken harness connector pins. Repair them, replace, solder them to the board. On mine, I didn't use them, rather, soldered wire pigtails to the board traces, and used a pair of "Molex" style connectors instead

2...Bad instrument regulator

3...Bad contacts in the IVR socket. On my cluster, the brass fingers were not making contact with board traces. I soldered jumpers across

4...Bad connection at gauge studs. Loosen/ tighten the nuts several times, or better, install "real" nuts

Ground........The 67 has two boards. It is originally jumpered to the casting by mounting screws and grounded from the casting 'with luck' through the cluster to dash frame mounting screws

I had some other photos, cannot find them

What you see here is the black soldered to the board jumpers over to the second board, and "goes off" to a ground point

The IVR socket has been jumpered to the traces

The blue white I believe is 12V igntion power coming into the board from the new Molex plug

There are many threads on here, repairing the connector pins

http://www.forabodiesonly.com/mopar/showthread.php?t=234045

 

[smitty040]

Minor update. Just received an order from Mr. Moparts and changing most of the interior bulbs. The guy I bought it off changed the headliner but never installed the dome light. Once I got the light mounted the light worked when the doors were open but did not work with the headlight switch. Would that and the dash light issue be a similar problem with the switch?

I plan to pull the cluster after goodguys this weekend and do some soldering like you suggested, clean all of the copper contacts, and install actual nuts on the gauge studs to see if that fixes those issues. I have a continuity tester to check the joints after soldering. Would a continuity test confirm if the fuel and temperature gauge are able to function properly?

 

[67Dart273]

the light worked when the doors were open but did not work with the headlight switch. Would that and the dash light issue be a similar problem with the switch?

I would not think so. However the headlight switch must be grounded. The door switches turn on the dome light by grounding the yellow wire. The connection on the light switch works same way

M Would a continuity test confirm if the fuel and temperature gauge are able to function properly?

Not exactly, but you can confirm that everything is getting "connected" that should be. There is a way to determine if the gauges are halfway accurate. There are three resistances which were in the old Mopar test rig.

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

So you get the cluster together, hook the cluster to battery ground, and the switched 12V going to the IVR up to battery, and then put these resistors in from the sender connections to ground. All the gauges (if equipped with oil) are same, so 23-25 ohms should give you 1/2 scale, 10-13 or so should give you full scale.

 

[smitty040]

Update: Changed the headlight switch yesterday and got both a working dome light and dash lights. Looking into the solid state limiter from RTE (even if its not needed i hear it is good to upgrade it while the dash is out) to see if that cures the temp and fuel gauge issue along with the soldering that you have mentioned to sure up the connections to the circuit board. Still need to get the steering wheel pulled to trace the wire for the horns to find out why it will not ground when the ring is pressed. I'll change the gear selector light bulb when I am in there and I should have 90% of my lights working in the car now.