Fuse Blows!

-
SpeedThrills

SpeedThrills

FABO Gold Member
FABO Gold Member
Joined
Jun 3, 2008
Messages
2,584
Reaction score
1,452
Location
Very South Jersey
My 74 Dart Sport, which is cloned into the Duster in my avatar, just started blowing the fuse that handles the turn signals, back up lights, heater blower and the wipers. I only have the turn signals and back up lights on the car; the heater and wipers aren't on it.

The fuse blows a couple seconds after the key is turned on with neither the t/s or back up lights on.

So, this tells me that there is a dead short before or at the back up light switch, before or at the turn signal switch, or before where the wiper or heater switches were.

I have a wiring diagram and have begun to look at it. There is no legend with the diagram, but I'm sorta figuring it out.

This just occurred, and I want to take it to a show Saturday (It's NOT a show car, just want to take it!), so I thought maybe I could save some time by asking on here if there is anything that is a common issue. I can live without the back ups, but I'd like to have the turn signals.
 
Thinking further, tomorrow I’ll disconnect the steering column harness and then the connector to the bu light switch. Maybe that will narrow it down.
 
Do you have a 74 service manual? Here's what it says about fuses

VL_fuses.jpg
 
I would pull the TS flasher, and take a look at your backup harness path. Either auto or stick, will have a harness down the firewall, over the transmission hump, and with auto, connect to the 3 pin neutral safety/ backup switch, and with a stick just connects to the 2 pin reverse switch on the transmission

If that gets you nowhere, "I guess" pull the connector off the heater/ AC controls. But the short MIGHT be some odd thing in the harness before "it gets" to any of that.

How about radio? Pull that connector FOR SURE especially if it is aftermarket
 
SpeedThrills said:
My 74 Dart Sport, which is cloned into the Duster in my avatar, just started blowing the fuse that handles the turn signals, back up lights, heater blower and the wipers. I only have the turn signals and back up lights on the car; the heater and wipers aren't on it.

The fuse blows a couple seconds after the key is turned on with neither the t/s or back up lights on.

So, this tells me that there is a dead short before or at the back up light switch, before or at the turn signal switch, or before where the wiper or heater switches were.

I have a wiring diagram and have begun to look at it. There is no legend with the diagram, but I'm sorta figuring it out.

This just occurred, and I want to take it to a show Saturday (It's NOT a show car, just want to take it!), so I thought maybe I could save some time by asking on here if there is anything that is a common issue. I can live without the back ups, but I'd like to have the turn signals.
Click to expand...
Not sure where You are, or if You are Worried for Certain Reasons, but hand signals are legitimate ( where I am) Now using them for brake lights? These days, especially after dark? I don't know about that, and your tag light bulb is a Must... I've been playing with these cars since a big block Was a daily driver. And Raised a LOTTA HECK!!!!!!! These Days? EVERYONE has a phone, and I Don't like stopping and Talking to People. Dell (67Dart273) is one of the Baddest electronics Men here... So that's all I got Brother!
 
Last edited:
If the fuses keep blowing, send them over here to my wife, she needs a few lessons in that area...
 
What's the difference between a bonus and a *****???


Your wife will always blow your bonus...
 
All great ideas above. @67Dart273 got me thinking when he said to remove the flasher. I had a shorted out flasher last spring that turned itself into an easy-bake oven when it failed. There are two flashers, one for the emergency flashers and one for the turn signals. I think it was my emergency flasher that failed. Remove them both when you check.
 
67Dart273 said:
Do you have a 74 service manual? Here's what it says about fuses

View attachment 1716006306
Click to expand...
No service manual, just the wiring diagram. I don't remember where I got it, but I have this info. I'm 63, getting CRS. :rolleyes:
67Dart273 said:
I would pull the TS flasher, and take a look at your backup harness path. Either auto or stick, will have a harness down the firewall, over the transmission hump, and with auto, connect to the 3 pin neutral safety/ backup switch, and with a stick just connects to the 2 pin reverse switch on the transmission

If that gets you nowhere, "I guess" pull the connector off the heater/ AC controls. But the short MIGHT be some odd thing in the harness before "it gets" to any of that.

How about radio? Pull that connector FOR SURE especially if it is aftermarket
Click to expand...
I already pulled the flasher, but that would get juice when the t/s are on. The fuse blows just after turning the key on, b/u and t/s off.
It was a 3 on-the-tree car, it's a 727 now. I wired it like a factory auto trans car. It worked fine until a couple days ago, but I'll check it.
The heater wiring isn't connected to the controls, no heater in the car anymore. I'll check it too.
I forgot about the radio. But that's because it's a radio delete car. Nothing but the "Internal Combustion Orchestra". :)
No reverse indicator light either.
All this is why I'm going to disconnect the steering column harness (to the t/s switch), and the b/u light harness, one at a time, to see if I can isolate it.
Where this circuit gets power from is what's hard for me to find on the diagram. I'll look closer at that, too. I think the short is along that part, but who knows?
Ironracer said:
Not sure where You are, or if You are Worried for Certain Reasons, but hand signals are legitimate ( where I am) Now using them for brake lights? These days, especially after dark? I don't know about that, and your tag light bulb is a Must... I've been playing with these cars since a big block Was a daily driver. And Raised a LOTTA HECK!!!!!!! These Days? EVERYONE has a phone, and I Don't like stopping and Talking to People. Dell (67Dart273) is one of the Baddest electronics Men here... So that's all I got Brother!
Click to expand...
I'm in Very South Jersey, per my avatar. :poke: :lol:

Hand signals are probably legal, but confusing sometimes. Could be a lot of people at the show.
Murray said:
Pull out the bulbs.
Click to expand...
The fuse blows without the b/u's or t/s's on. I'll keep it in mind as I progress.
krazykuda said:
If the fuses keep blowing, send them over here to my wife, she needs a few lessons in that area...
Click to expand...
It's a memory issue; she was probably good at it before you got married.

Thanks everyone. I'll get to this later today.
 
Last edited:
ACME SS said:
All great ideas above. @67Dart273 got me thinking when he said to remove the flasher. I had a shorted out flasher last spring that turned itself into an easy-bake oven when it failed. There are two flashers, one for the emergency flashers and one for the turn signals. I think it was my emergency flasher that failed. Remove them both when you check.
Click to expand...
Thanks. You just posted while I was typing. Flashers get juice when t/s are on, fuse blows without them on.

BTW, hazards work fine, including indicating arrows on dash, but they are on different fuses.
However, the indicators don't work when the t/s are on. All dead.
 
SpeedThrills said:
Thanks. You just posted while I was typing. Flashers get juice when t/s are on, fuse blows without them on.
Click to expand...

Just for grins, disconnect the plug behind the driver side kick panel. That eliminates anything to the rear, if it still blows then you have narrowed it to one section of the car. If it does not blow it would be safe to assume it is to the rear.

Have you done any interior work, like carpet putting sill plates back on? It has happened in the past where the wires that run along the driver side get pinched under the sill plate, sometimes it shows itself almost immediately, sometimes it takes a bit for the edge of the plate to work through the insulation and ground things out.

Just a thought.
 
I found it!

The fuse didn't blow when I put one in just now. Hmmm. It blew 3 the other day.

I tried jiggling the connector on the firewall that goes down to the neutral safety/reverse light switch while watching the b/u lights with a mirror. They flickered. Upon disconnecting the connector to inspect, I found one of the male spade connectors trying to "escape". As a result, the exposed connector had been touching the brake line that goes to the RF wheel.

Earlier this week, I had the trans pan down, and moved those wires away from the headers. Apparently, that's when connector and its exposed spade connector started touching the brake line.

Not blowing the fuse today was because I had the intake off after the trans pan job, and inadvertently jiggled those wires so they weren't touching the brake line.

I got lucky on this one! It was the first thing I checked!

Thanks for the ideas and suggestions.
 
You must log in or register to reply here.
-

Back
Top