Electrical Gremlin

[PurpleBeeper]

70 Road Runner rally dash car. All of a sudden, the turn signals including outside bulbs, dash indicators and hood turn signals stop working. At the same time, all the dash gauges go dead. A few minutes later, everything works….then doesn’t again. I’ve obviously got a loose wire or ground. Where should I start looking? Thanks for any tips!

 

[pnora]

Check the connector at the steering column. Sounds like you are losing a keyed 12 volt feed.

 

[BeepBeepRR]

70 Road Runner rally dash car. All of a sudden, the turn signals including outside bulbs, dash indicators and hood turn signals stop working. At the same time, all the dash gauges go dead. A few minutes later, everything works….then doesn’t again. I’ve obviously got a loose wire or ground. Where should I start looking? Thanks for any tips!

Factory harness or an aftermarket Painless type?

 

[PurpleBeeper]

Factory harness or an aftermarket Painless type?

Factory repro harness in the dash with 5V home built diode (?) instead of voltage limiter

 

[Gold Rush]

Gages and turn signals are two separate power levels but originate coming out of the ignition switch at the same place. As said earlier, that connector at the steering column is the first place I'd check. Should be fairly easy to run down fault with a volt/ohm meter (VOM) and the factory service manual.

 

[72RoadrunnerGTX]

As mentioned, the turn signals and voltage limiter are both powered on the accessory ignition switch feed circuit with one common connection at the ignition switch Molex connector (black wire) at the bottom of the steering column. That wire and the red wire switch feed terminals are common failure points. Another example of under current rated terminals for the expected current load.

 

[Xp29h]

Anytime I see the word “gremlins” I think of a ground issue! The folks above are spot on too! But after many crazy ground issues with things working then not at all or partially, I rewired the 69 and used many good clean ground terminals and no more gremlins. May not be your issue, but always a good check! Good luck!

 

[72RoadrunnerGTX]

In this case, as described, can’t be a ground issue, all of the mentioned effected bulbs and dash gauges are grounded separately or locally. Nothing ground related in common to each other to explain them all coming and going at the same time.

 

[BB69R/T]

another check would be the terminals on the back of the ammeter. I had a similar situation and the power cut off to the entire car, engine and all. A solder connection on the back post of the ammeter failed becoming loose. almost like an on/off switch. I'd jiggle the connection and power would be restored. I had to have the ammeter replaced. Good Luck. hope this helps.

 

[WileERobby]

Before you go chasing a gremlin... start with the bulkhead connector.

 

[PurpleBeeper]

I’ve bypassed the ammeter already, so #1 plugs at bottoms of column #2 bulkhead connector. I will try this weekend

 

[WileERobby]

Back in the day, had a similar problem with an almost new Ford Granada. Checked the bulkhead connector, SHAAZZAM !! sparks like the 4th of July. Was not properly tightly connected.