Electrical Nightmare

[Steven Tuttle]

Hello guys,

so my 72 roadrunner is giving me issues still, I posted in here a little while ago about some electrical problems.

So my horn is still not working, for the electrical guys, should my vehicle have a ground strap on the column what does that do exactly. Also what makes contact in the steering wheel for the horn to ground?

I purchased an original ralley dash, my color was off and also broken, and all my gauges were working so I swapped my good hardware on the new cluster. I replaced the turn signal switch and when the headlights are on both turn signals on the driver side are weak, but the right is okay. When the headlights are off both work great and I cannot figure it out. My dash lights were not working with the headlights on, and I replaced the 5 amp fuse, but every time I was turning the headlights on the fuse would blow. I didn't do anything different and I tried it today and its working? Where should the ground be for the tail lights? Im still new to the old Mopar community and unfortunately I did not grow up in the good old days when these beautiful cars were produced. So im learning as I go.

I also purchased a new radio from classic industries, and I'm assuming that the antenna acts as a ground, because on the new radio harness it has a ground wire and even without it plugged in the radio still works? I also smelled something burning behind the dash, but could not find the source.

 

[dadsbee]

I believe it was you that I already described this too and supplied pictures.... but yes there is a ground strap from column mounting bolt to dash bolt as the column bracket is mounted in plastic sliders so you need the jumper. That puts negative/ground into the column.. through the bearing and into the wheel mounting shaft From there the ground makes it to the bottom of the horn ring. When you press the horn button that ground continues to the other side of the horn ring contact which connects to the contact ring under the steering wheel... which runs against a roller in the turn switch mechanism. That roller takes ground through the black wire in the turn signal harness to the ground/negative terminal on your horn relay. Positive is always live at the horn relay.

 

[moparedtn]

Mine only works at about the 6 o'clock position when the wheel is turned.
Guess I ought to fix that one day.

 

[kiwigtx]

Mine only works at about the 6 o'clock position when the wheel is turned.
Guess I ought to fix that one day.

Or do this....

 

[moparedtn]

Oh damn

 

[Steven Tuttle]

I believe it was you that I already described this too and supplied pictures.... but yes there is a ground strap from column mounting bolt to dash bolt as the column bracket is mounted in plastic sliders so you need the jumper. That puts negative/ground into the column.. through the bearing and into the wheel mounting shaft From there the ground makes it to the bottom of the horn ring. When you press the horn button that ground continues to the other side of the horn ring contact which connects to the contact ring under the steering wheel... which runs against a roller in the turn switch mechanism. That roller takes ground through the black wire in the turn signal harness to the ground/negative terminal on your horn relay. Positive is always live at the horn relay.
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Your probably right, I forgot I posted one before. Thank you, in reference to the turn signals when the headlights are on and the left side blinks very slow but the right side works fine, then with the headlights off they both work fine.

 

[Dennis H]

If your 72 has a Bulkhead Connector on the firewall, pay attention to it. It can be a source of other issues. At least examine it gently. Carefully remove three banks without breaking tabs and spray with electrical cleaner. Examine for anything melted. Reinstall. This will not fix your specific signal and other issues. Concerned about a hot smell. Keep an extinguisher handy just in case.

 

[Dennis H]

Update?

 

[Steven Tuttle]

Update?

I will have an update for you tomorrow, have not gotten the chance to work on it yet! I’ll definitely let you know!

 

[Steven Tuttle]

Update for everyone, so I connected the ground strap horn still not working, and the turn signals are still not working right.

 

[dadsbee]

So get a meter out and follow the ground path. First a quick check at the horn relay, meter on both the + and - terminals and get someone to push the horn ring. Do you get 12volts? If so it's your relay. If dead there then meter + lead to + on battery or other positive feed and start at the ground jumper to column with the negative wire. 12 volts on column then move on to the horn pad and see if you still have 12volts at the lower ring. Then the upper ring while pushing it sideways to contact the lower. 12volts there.. then check the wire attached that goes to the brass ring on the bottom of the wheel. 12 volts there then you have an issue from the roller, it's wire, etc to the horn relay. I'm laying odds on the roller and your turn signal switch..

 

[Slowride 262]

I'm betting on the firewall harness is melted inside.

 

[mpro69rr]

Do yourself a favor and just get a new harness. I had all kinds of electrical problems including two shorts that I couldn't find. I talked to a mobile service guy and he wanted $400 to start trying to find it. I looked up how much the harness cost and it was $400 so I got the harness because the guy couldn't guarantee anything. I put the harness in which wasn't a bad job if you take the dash apart. Once I got it in everything worked and the two shorts went away!

 

[ckessel]

Old car with aging electrical problems. Lots of ground and connection issues. One area for the light is where the socket is attached to the lamp housing. Over time you get corrosion going there killing the ground. You are in a damp area which adds to it. Time to boot the old, add in new and add in more grounds plus make sure the grounds have clean connections to the components. No paint, rust, goo etc. Replace your switches too. Contacts wear out over time.