ATTENTION: weirdest Stuff going on

Stoffauge

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Hey all together.

Be careful it´s gonna be wild and crazy what I will tell you.

1971 Sport Fury 383-4

Starting Point : All lights work as they should, turn signals, hazards etc.

Since then I added the following things:

TTI Exhaust (no effect I guess)
Tank incl. sending Unit (works - tested with gauge)
headlight door motor - works with igniton and lights on
Autometer tachometer
put in heater core and plugged in the heater/ac switch (blower/fan works fine)

Now please pay attention I will tell you what I saw the car doing today:

All lights are kinda messed up now (gonna tell about different problems):

As soon as the battery is plugged on the red "fuel" is shown in the Speedo - if I hit the brakes it turns off and the brake lights turn on and other way round
all lights still turned off -> ignition on -> light switch still off but rear lights turn on - no clue why.
after like 10sek ignition on the headlight delay relay is going crazy with clicking - stops when turning on the engine
turn signals turn on with igniton on but don´t flash!! - while hazards work fine ignition on and off.
engine runnig - just one of the 4 brake lights work!

Some other weird combinations where happening too but can´t really remember . And I think you guys heard enough :D

I have actually don´t even a clue where to start because all lights worked fine before I did the stuff above.......


Desperately looking for your help.

Thanks
 
I did one after another but check the lights in between the repairs . Tti fits perfectly no cable is close . But good call this could create craziness too
 
Has a ground wire been dislodged? Grounding issues can, and do, cause "weird" electrical problems. If electricity cannot follow the proper (designed) path, it will take the path of least resistance. This can cause power to flow to groung through any available circuit. An extra ground or two will never hurt.
Just a couple thoughts. Lindsay
 
It sounds like a short that started when something that was not connected was connected.
I would try disconnecting the newly connected parts and then checking the lights each time.
When the problem goes away, you've found your shorted wiring.

Tank sending Unit
headlight door motor
Autometer tachometer
heater/ac switch (blower/fan works fine)
 
It sounds like you’ve been under the dash.
A poorly connected ground wire (or another) may have become disconnected or shorted.
Re-trace your steps in connecting the tach and your time under the dash.
I am assuming that you only plugged the vacuum lines in disabling/bypassing the heater control (you should only have to plug the input vacuum line into the mode control switch).

Investigate and report back.
 
I'm sorry if this is too obvious but have you checked your fuse box? A while back I had mysterious light issues in the dash and it looked like power was back fed through a ground or something. Turned out to be a burnt fuse and once replaced, all was well.
 
One piece that I would check also is the low fuel warning relay. It's located near the passenger ashtray (assuming it is like my '70). Since that is really near the Heater/Ac box, that's in range of getting "hit" when you changed the heater core. I don't know as it is the cause of all this, but it hit me as something I would check.

Otherwise, I'm thinking grounds to dash and body. I emphasized "and body" so you start checking it all. I'd also check the fuses (easiest thing to do) and generally poke around looking at the wiring. Make sure all the plugs at the bulkhead connector are in place and secure.
 
The only time I had that many strange electrical problems at once was when I put a double contact bulb (1157) into a socket that need a single contact (1156) and resulted somehow to a backfeed of power through the ground system. Nothing fried but when I hit the brake pedal like 5 things started working when they shouldn't. I'm sure there is a logic to how this happens but it just evil magic too me. At least for me it all started with a brake pedal but it seems yours starts with a connection to the battery so could be any constant-on circuit.

So while your checking grounds you might also consider if the power is going where it should.
 
The only time I had that many strange electrical problems at once was when I put a double contact bulb (1157) into a socket that need a single contact (1156) and resulted somehow to a backfeed of power through the ground system. Nothing fried but when I hit the brake pedal like 5 things started working when they shouldn't. I'm sure there is a logic to how this happens but it just evil magic too me. At least for me it all started with a brake pedal but it seems yours starts with a connection to the battery so could be any constant-on circuit.

So while your checking grounds you might also consider if the power is going where it should.

I had the very same problem on the Imperial a couple of years ago.
 
I would check for a poor ground as mentioned. You may have disconnected something while installing the heater core. I would start by getting the FSM and finding where all the grounds are. Poor or no grounds will result in a back feed through another circuit that is properly grounded.
If the grounds are good start looking for melted wiring perhaps you pinched something when you did the heater core.
This may be difficult to find and lots of patience and or beer is required.
 
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