71 Swinger dash lights pulsate when turned on

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73SlantSwinger

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Need some help on a dart I picked up a few months back. The other night I noticed when I pulled the knob for the parking lights and also the headlights, the cluster lights pulsate back and forth (they go dim to bright) and when I try the turn signals the indicator arrows are not illuminating at all although I can hear the ticking and the outside bulbs are working and functioning fine. All guages on the cluster work, no issues there. The only thing that I've had done since I've owned it is I had a local shop install a tach and oil psi/water temp autometer guages. Any idea's on where to start? thanks
 
73SlantSwinger said:
Need some help on a dart I picked up a few months back. The other night I noticed when I pulled the knob for the parking lights and also the headlights, the cluster lights pulsate back and forth (they go dim to bright) and when I try the turn signals the indicator arrows are not illuminating at all although I can hear the ticking and the outside bulbs are working and functioning fine. All guages on the cluster work, no issues there. The only thing that I've had done since I've owned it is I had a local shop install a tach and oil psi/water temp autometer guages. Any idea's on where to start? thanks
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You'll have that. Mopar alternators don't charge much at idle. Try giving it a little gas at idle or pop it in neutral to see if it get's better. Everything in the system should be checked, components and connections alike or it may need a regulator or a alternator but don't just go ahead and replace those without checking out the system.
 
You have multiple problems. The dash lights are likely "reading" the changing battery voltage. This is often caused by the classic "voltage drop" problems in Mopar wiring. The short story is that the voltage regulator MUST see "same as battery." ANY resistance/ voltage drop in either the harness or ground circuit can cause OVER charging (over voltage) and or pulsation

If you have an older (69/ older) electro--mechanical regulator, the regulator itself can do so.
 
Your indicator lamps---did your car originally have fender turn indicators? The dash ones may not have sockets/ bulbs installed.

Otherwise, they surely are a problem right in the cluster, bad bulbs, corroded sockets and contacts, etc

The indicator lamps are fed from wires branched off from the front lamp feeds coming out of the turn signal switch.

Has someone "been in there" hacking up wiring?
 
Doesn't look like anything has been messed with as far as I can tell. It's a 45K mile slant six car that was gone through in the early 2000's, beautiful car. I tried replacing the bulb for the turn signal socket I could get to from underneath the dash but that did nothing, still won't light up. Car doesn't have fender indicator's. I just discovered this the other night as I have only driven it a few times since I got it, and never at night.
 
73SlantSwinger said:
Doesn't look like anything has been messed with as far as I can tell. It's a 45K mile slant six car that was gone through in the early 2000's, beautiful car. I tried replacing the bulb for the turn signal socket I could get to from underneath the dash but that did nothing, still won't light up. Car doesn't have fender indicator's. I just discovered this the other night as I have only driven it a few times since I got it, and never at night.
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I would start by making sure the cluster has a good ground to body.
Lack of a solid ground can cause all kinds of whacked out stuff.
 
As mentioned, probably two different problems, but, a bad ground might cause both symptoms. I've seen some weird dash light problems caused by the potentiometer in the light switch too. Might not be a bad idea to pull the cluster and bench test everything. You can add a ground wire, an upgraded IVR, and put in some new bulbs and sockets while you're at it. Maybe even get the stock gauges to work. If you do pull the cluster, be careful unplugging the left side of the circuit board that year. The outer edge of the board is poorly anchored and can break fairly easily. Spray some penetrating oil on the plug and work it off gently.
 
There are several threads on the site dealing with voltage drop. Definitely a good place to start.

Pulling the cluster has its benefits as well. You can check all the connections and repair as needed. Also some good threads about common cluster repairs.

As others have said it’s probably multiple problems, but those are the two most likely problems.
 
When you rev the engine to 2000 rpm, does the pulsing go away?
 
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