my 94 bronco will start at initial cold start. the air pump will run i noticed my air bag light is on and my horn does not work. my problem is that when i turn the switch for my right blinker or if i pull the headlight switch on the truck stalls and shorts out i believe. I go to turn the truck on but it only cranks and will not restart.i wait i couple hours later and it will restart but only run for atleast half an hour.

 

Sounds like the vehicle has an poor electrical connection that when it heats up, opens enough to cause it to quit running.
The best place to start is right from the battery. Check, means loosen move and retighten, every connection from ground side and hot side that you can see/trace from the battery to the inside of the vehicle. Don't overlook the grounds to the sheet metal under the hood. If you find the problem area , let us know so others may benefit from your experience. Thanks, hanky

 

i had also recently installed headers on this truck i have checked again and again for bad connections i also replaced the positive terminal because it was corroded and broken i have tested the alternator as well it is pushing 14.73volts but when i turn on an electrical load and the vehicle doesnt shut off my battery meter on the dash goes way below the halfway mark.

 

You have a high resistance connection somewhere, and it appears to be in the hot-positive side of the system. You need to check further up from where the positive cable connects to supply the vehicle . What about the connection at the main fuse/relay box? Sometimes moisture can corrode connections that are not always visable.

 

i was taking a look at the all the fuses one of the 30 amp fuses looks like it may be corroded i was wondering what kind of fuses it uses r they glass fuses? i tried to remove it but it seemed very hard to remove im wondering if i may have arched something such as the alternator that made that fuse blow or something but if it was a glass fuse would it still operate the way it does now and when it loses connection thats y the vehicle shuts off

 

sounds like maybe the alternators not getting to the battery. have you try'ed taking your battery cable off with truck running. just a though

 

I don't like telling guys this , but DON'T REMOVE THAT BATTERY CABLE WHEN THE ENGINE IS RUNNING TO TEST THE ALTERNATOR. the reason is the alternator now has no control over output and can self destruct with an over current condition. Not a good move to do.
I am not sure if your vehicle has a junction where the positive cable going into the vehicle splits into two fusable links than inside to feed the rest of the vehicle.
Trace that positive cable from the battery and alternator and see if it doesn't come to that junction with a fixed post and then the wires divide. Corrosion at that junction could very well be the problem.

 

well hanky you may be right but i have never had one self destruct in 45 yrs of doing fords gzz i must be one lucky "sob" thanks for that

 

An easier way to see if an alternator is putting anything out is to place a screwdriver near the back end and if you feel a magnetic hold on the tool the alt is putting out. Using either way there is no way to determine just how much its putting out. A quick way is to get one of those gauges you lay on the battery/alt cable and see right then and there what you're getting. Its nice because you don't have to disconnect anything and its safe.

 

Thanks for the tips guys but hanky was right i had high resistance in the circiut i found my left front sidemarker bulb out and the elctrodes inside were touching grounding out the circiut when it got hot enough i replaced both left and right side bulbs also the turnsignlas bulbs as they havnt been touched since 1994! i also changed my ground cables in the process which i found on another forum they were corroded from the inside looked like cancer! hanky is also right about disconnecing the power cables i went over to my shop and put on my battery tester which also can read alternator voltage i found its good with no laod but when i have my ac on or foglights on the battery meter on the dash moves down but when i give it gas it goes up the alternator only puts out 12.50 V i was told the regulator inside is bad so now im going to change the alternator and drivebelt as i am there anyways