Charging system problem in 79 Bronco

[erin7747]

Am the second owner of a beautiful 79. Have had it for almost a year. Ever since I drove it home, the turn signals have worked when they feel like it. And on occasion, I'll wake up to a dead Optima battery. Last week, after another dead battery day, I replaced the alternator, voltage regulator, and the battery. It ran great for a week, until my radio started to turn off and on, lost turn signals, and finally I parked to run into a store. When I came back out, It wouldn't start. Was able to jump it, but kept stalling out. Everytime I jumped it, it got harder and harder to jump, until I couldn't jump it any more, and had to push the beast home! Took the new alternator down to Autozone. They tested it and said I musta got a bad one. So I was happy that's all it was. They gave me another one that tested good. Put it in and jumped her. She ran for about 20 mins. in the driveway and stalled again. I'm at a loss. I have very limited skills in this area. I am so in love with my bronco (Burnadette is her name). She's the most beautiful vehicle I've ever owned. I've got no money left after throwing these new parts at her though, and can't bring her to a shop. Any suggestions?

 

[Yardape]

I'd suggest getting ahold of a list with all the ground locations and check everyone of them for tight and clean connections. That is critical

 

[erin7747]

I'd suggest getting ahold of a list with all the ground locations and check everyone of them for tight and clean connections. That is critical

Thanks Yardape for your quick response. Where can I find such a list at a fair price?

 

[Yardape]

You can have a look around on ebay for a electrical and vaccum troubleshooting manual for your year truck. In the meantime you can check the obvious ones maybe you will get lucky.

 

[erin7747]

You can have a look around on ebay for a electrical and vaccum troubleshooting manual for your year truck. In the meantime you can check the obvious ones maybe you will get lucky.

Turns out, I either screwed up putting in the voltage regulator and blew it, or that bad alternator blew it. Because, I put another regulator in and she's charging at 14.9 now. Still think there's a wiring issue though. I have no dome light, no reverse lights, and cigarette lighter. Is there a hand signal for reverse, or do I just roll down my window and yell "BOOP BOOP BOOP BOOP!" :lol: ? haha. So at least i got the charging system back on track. Thanks Yardape for your ground wire suggestion. Still think that's valid advice. I must have a draw somewhere. If something isn't grounded, will it still function? In other words, should I be checking the grounds to the dome light, cigarette lighter... first?

 

[erin7747]

Turns out, I either screwed up putting in the voltage regulator and blew it, or that bad alternator blew it. Because, I put another regulator in and she's charging at 14.9 now. Still think there's a wiring issue though. I have no dome light, no reverse lights, and cigarette lighter. Is there a hand signal for reverse, or do I just roll down my window and yell "BOOP BOOP BOOP BOOP!" :lol: ? haha. So at least i got the charging system back on track. Thanks Yardape for your ground wire suggestion. Still think that's valid advice. I must have a draw somewhere. If something isn't grounded, will it still function? In other words, should I be checking the grounds to the dome light, cigarette lighter... first?

Ok, take that back. The truck was doing great yesterday after I put in new voltage regulator. Today, battery is dead as a door nail again! Maybe a girl that sucks at working on trucks has no business owning a classic Bronco?

 

[Runnin'OnEmpty]

Erin, don't give up, fixing stuff is all part of the fun in having these old trucks.

You obviously have a short somewhere that's draining your battery.

Try connecting a multimeter or test light between the negative battery cable and

the negative post, and see what the reading is. It'll probably show a drain. Then it's

just a matter of pulling fuses one by one until you find the circuit with the short.

Good luck and let us know what you find......

 

[BroncoJoe19]

Hang in there... there is a certain satisfaction that one gets by fixing his/her own vehicle.

Here is a list of grounds for a '92 - '96 bronc

I took a look in my Haynes manual.

They list 10 separate grounds... A-J.

A. Starter mounting bolt

B. Right front of Engine compartment near the battery

C. Lower left front of engine

D. Right front of engine compartment on upper radiator support.

E. Left front of engine compartment Upper radiator support

F. Bottom of cowl panel

G. Rear of left fender apron

H. Behind bottom of right cowl panel

I. Left rear corner of cargo area near rear lamp assembly

J. Under center rear of vehicle on rear cross member.

Ground number and locations in 1990 Bronco EVTM

G100 LH side of Radiator support

G101 RH side of Radiator support

G102 RH side of Radiator support

G103 LH rear side of engine, near knock sensor

G104 LH rear side of engine compartment, near electronic engine control (EEC) module, on the left fender close to the firewall

G105 LH Side of engine

G106 RH fender apron, near voltage regulator

G107 RH fender apron, at starter relay

G108 RH fender apron, at voltage regulator

G109 RH fender apron

G201 LH rear side of I/P (looking at the diagram it is at the bottom of the driver's side dash assembly. Screwed to the bottom edge, just to the left of the steering column. It is the ground for the instrument cluster)

G202 Behind RH cowl panel

G203 RH rear side of radiator support

G204 On steering column

G205 Behind Center of I/P (Dash), near speed control amplifier

G400 LH side of cargo area, near rear light assembly

G401 Below LH side of cargo area, near crossmember

G500 Inside driver's door, near left door speaker

How to find a Battery Drain... short to ground

1. Get a 12v. light bulb that has wries on both ends, (a bulb in a wired socket) I use a trailer clearance light.

2. disconnect the ground cable from the battery

3. dissconnect the positive cable

4. connect the light in line bewteen the postive battery terminal and the positive cable.

5. reconnect the negative battery cable.

NB: while you have them off, examine and clean if necessary.

It is OK for the bulb to glow, but if it shines, there is a short.

The brighter it shines the greater the draw, or drain.

There is always a slight drain on the battery for things like Keep Alive Memory for the computer, radio presets, car alarm, remote starter etc. hence the glow is OK.

6. start pulling fuses, when the light goes out (or rather just down to a glow) you found the circuit that the short is in.

7. If pulling fuses doesn't work, then pull relays, and finally the connections to the alternator.

NB: you'll have two sets of fuses and relays. One set under the hood in the power distribution box, and another under the dash, usually driver's side.

NB: different color fuses are different amperages, and should not be interchagned!

Your owner's manual should have a diagram depicting what items are protected by which fuse.

Once you have narrowed the problem down to a particular circuit, start examining the wiring going to the components. See if any are frayed and contacting metal, try to eliminate sections, by disconnecting connectors, switches, bulbs etc.

 

[erin7747]

Hang in there... there is a certain satisfaction that one gets by fixing his/her own vehicle.
Here is a list of grounds for a '92 - '96 bronc

I took a look in my Haynes manual.

They list 10 separate grounds... A-J.

A. Starter mounting bolt

B. Right front of Engine compartment near the battery

C. Lower left front of engine

D. Right front of engine compartment on upper radiator support.

E. Left front of engine compartment Upper radiator support

F. Bottom of cowl panel

G. Rear of left fender apron

H. Behind bottom of right cowl panel

I. Left rear corner of cargo area near rear lamp assembly

J. Under center rear of vehicle on rear cross member.

Ground number and locations in 1990 Bronco EVTM

G100 LH side of Radiator support

G101 RH side of Radiator support

G102 RH side of Radiator support

G103 LH rear side of engine, near knock sensor

G104 LH rear side of engine compartment, near electronic engine control (EEC) module, on the left fender close to the firewall

G105 LH Side of engine

G106 RH fender apron, near voltage regulator

G107 RH fender apron, at starter relay

G108 RH fender apron, at voltage regulator

G109 RH fender apron

G201 LH rear side of I/P (looking at the diagram it is at the bottom of the driver's side dash assembly. Screwed to the bottom edge, just to the left of the steering column. It is the ground for the instrument cluster)

G202 Behind RH cowl panel

G203 RH rear side of radiator support

G204 On steering column

G205 Behind Center of I/P (Dash), near speed control amplifier

G400 LH side of cargo area, near rear light assembly

G401 Below LH side of cargo area, near crossmember

G500 Inside driver's door, near left door speaker

How to find a Battery Drain... short to ground

1. Get a 12v. light bulb that has wries on both ends, (a bulb in a wired socket) I use a trailer clearance light.

2. disconnect the ground cable from the battery

3. dissconnect the positive cable

4. connect the light in line bewteen the postive battery terminal and the positive cable.

5. reconnect the negative battery cable.

NB: while you have them off, examine and clean if necessary.

It is OK for the bulb to glow, but if it shines, there is a short.

The brighter it shines the greater the draw, or drain.

There is always a slight drain on the battery for things like Keep Alive Memory for the computer, radio presets, car alarm, remote starter etc. hence the glow is OK.

6. start pulling fuses, when the light goes out (or rather just down to a glow) you found the circuit that the short is in.

7. If pulling fuses doesn't work, then pull relays, and finally the connections to the alternator.

NB: you'll have two sets of fuses and relays. One set under the hood in the power distribution box, and another under the dash, usually driver's side.

NB: different color fuses are different amperages, and should not be interchagned!

Your owner's manual should have a diagram depicting what items are protected by which fuse.

Once you have narrowed the problem down to a particular circuit, start examining the wiring going to the components. See if any are frayed and contacting metal, try to eliminate sections, by disconnecting connectors, switches, bulbs etc.

Thanks RunninonEmpty and BroncoJoe foe the encouragement and help. So glad I found this sight. Am real busy with work right now, so for now I'm just disconnecting the battery while its parked. I'll let you know how I'm doing finding this draw.

 

[78 blue beast]

I actually had the sme problem with my 78. I ran a ground wire from the negitive post on the battery to the alt. there was a GRD stud that I mounted it to. Seems to have solved the problem. Let us know if your draining problem still exists.

 

[MIL1ION]

MY guess is the battery as well.

The Ford Ignition system requires at least 6 volts to run once that is gone the engine quits.

Before making any tests always make sure the battery is fully charged by a battery charger.

 

[Johnny Reb]

Am the second owner of a beautiful 79. Have had it for almost a year. Ever since I drove it home, the turn signals have worked when they feel like it. And on occasion, I'll wake up to a dead Optima battery. Last week, after another dead battery day, I replaced the alternator, voltage regulator, and the battery. It ran great for a week, until my radio started to turn off and on, lost turn signals, and finally I parked to run into a store. When I came back out, It wouldn't start. Was able to jump it, but kept stalling out. Everytime I jumped it, it got harder and harder to jump, until I couldn't jump it any more, and had to push the beast home! Took the new alternator down to Autozone. They tested it and said I musta got a bad one. So I was happy that's all it was. They gave me another one that tested good. Put it in and jumped her. She ran for about 20 mins. in the driveway and stalled again. I'm at a loss. I have very limited skills in this area. I am so in love with my bronco (Burnadette is her name). She's the most beautiful vehicle I've ever owned. I've got no money left after throwing these new parts at her though, and can't bring her to a shop. Any suggestions?

 

[Johnny Reb]

If you have a tilt steering column-----their could be your short. Also, next time you get out of it. Go around the back and check your brake lights. Sometimes the pedal will stick-causeing a dead battery

. You may also want to look inside at night and see-if your glove box light is on.Go over all the grounds . You can also get more then one bad part at the store. I got 5 bad starters in a row one time. If your brake pedal is sticking. Put some oil(make sure none gets on the pedal and you get all the drops cleaned up) on the pedal--bushing.You might also want to check you brake switch, they do go bad-causeing a dead battery.

Then you might have a bad battery. Good luck,Johnny

 

[Johnny Reb]

If you have a tilt steering column-----their could be your short. Also, next time you get out of it. Go around the back and check your brake lights. Sometimes the pedal will stick-causeing a dead battery. You may also want to look inside at night and see-if your glove box light is on.Go over all the grounds . You can also get more then one bad part at the store. I got 5 bad starters in a row one time. If your brake pedal is sticking. Put some oil(make sure none gets on the pedal and you get all the drops cleaned up) on the pedal--bushing.You might also want to check you brake switch, they do go bad-causeing a dead battery.

Then you might have a bad battery. Good luck,Johnny

I noticed that your bronco is a auto matic. One of the draw back the automatic has-is the starter does not get a good ground -because the starter is bolted to an aluminum bellhouseing(like on yours) . Get you a good copper batter terminal--about 2 feet long and get end put on it-to where you can bolt one end to your starter and one end to your frame. It helps alot aon your chargering system and starter . The aluminium has a tendency to corode and you loose your ground. Any vehicle that has alumium transmission case --should have a good ground -from the starter to the frame.