I have a 1995 Ford Bronco, I just replaced the battery because the other one had a dead cell. The new problem I've run across is, when I crank the truck it starts up and idles just fine but when I turn the headlights on the truck dies like the switch was a **** switch, when I use the turn signal to turn right the truck loses idle each time the light clicks, when I turn the headlights off I can hear the the fuel pump turn on, what could cause this and how do I fix it?
Headlight turn my Bronco off?!
- Thread starter Baleos
- Start date
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Xxxyank
Member
Check your battery cable connections for any crud and all your ground cables for any shorts... If you got a voltmeter, make sure you are getting at least 13 volts. If you don't have a voltmeter, you can either risk driving the truck to a parts store like autozone and they can field test your entire charging system or you can just unbolt your alternator (most likely the problem) and have them bench test it for you.
It's not unheard of, that a dead cell will form in an already weak battery because it is trying to over compensate for a bad alternator.
It sounds like your truck is running off your battery.
good luck
It's not unheard of, that a dead cell will form in an already weak battery because it is trying to over compensate for a bad alternator.
It sounds like your truck is running off your battery.
good luck
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Seabronc
New member
Weird problems are generally caused by poor grounding. As XxxYank said, with the engine running and using a voltmeter check from the battery (+) to the Battery(-), then from the battery (+) to a clean spot on the engine block. There should be virtually no difference in the reading. Also, if the alternator is putting out properly, you should get a reading of around 13.5 volts or a little higher. A difference in the two readings would indicate a bad battery (-) connection. if so, check the condition of the connections at both ends of the battery (-) cable. Remove the connections, clean with Emmery cloth and reconnect. Also check the point at which the cable goes into the lugs at either end, if there is any corrosion at that point replace the cable. You should also do the same with the battery (+) cable. There is also a grounding strap from the top at the rear of the engine to the fire wall, do the same with it. If the truck has a separate cable from the block to the frame do the same check with it. After you have cleaned and replaced those connections, check the battery voltage with the engine running. Again you should be getting 13.5 volts plus. If not, your alternator is probably bad. However, generally if the alternator goes bad it is due to the internal voltage regulator on your 3G alternator, it is easily replaced and a lot less expensive than a whole new alternator.
Good luck,
>-
Good luck,
>-Took it to a mechanic today and he said it could be a grounding issue, When I got the new battery I also replaced the old and worn out cable to starter/starter solenoid assembly which was essentially every cable that comes off the battery. Had the alternator checked and it was fine, I checked all the grounds from/to the battery and they were all fine. He said the solenoid wouldn't be the problem but I've seen post on the internet where they say it could be. I don't understand how my headlight switch would A. Shut my truck off instantly B. When I turn my headlights off I can hear the fuel pump turn on C.the right turn signal makes the engine lope every time it clicks but the left signal is fine. I even check and tapped my full brights which is the turn signal handle pulled all the way in and even that cut the engine. I can drive it just fine unless I need my headlights, which is every morning when I go to work, I also need to replace the Starter entirely since it wont kick over 60% of the time, it just sits there and whirrs until I stop trying to crank it. I hope this information can help everyone help me and we can figure this out, I can do all the work but I have to know a good place to start that I haven't been to already. If you need anymore information I'll try to give as much more as I can as this progresses. Thank you for the help. Also, could there be a relay issue? Just wondering.
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Seabronc
New member
You said all the grounds are good did you remove and clean all the contact surfaces?
Did you check the part of the cable where it goes into the lug? If there is any corrosion there replace the battery ground cable and be sure to clean the contact points.
A bad ground will cause a voltage drop, so when you turn on your lights, the voltage drop can make the voltage too low to operate the engine.
>-
Did you check the part of the cable where it goes into the lug? If there is any corrosion there replace the battery ground cable and be sure to clean the contact points.
A bad ground will cause a voltage drop, so when you turn on your lights, the voltage drop can make the voltage too low to operate the engine.
>-
Xxxyank
Member
it has to be some kind of grounding issue, if your charging system is good... If this wasn't happening before you did the battery switch, something might be crossed... then i would back trace everything... Did you do anything else? change bulbs, remove anything?
I know a guy once who was having light problems in an international scout & every time he hit his brakes all the lights would go out or flicker, etc. So one day at this IH wrench a thon, I showed up late & he had 6 guys pulling all his lights out. I mean everything was just hanging and dangling out of his scout, including his steering column, trying to figure out what was wrong... I asked him if he ever had good brake lights & he said yes but after changing the bulb, his lights starting doing this... so he showed me which one, well it turned out he was able to fit a 156 into a 157 and was grounding out all his lights every time he hit the brakes... Lol not to say this is the case here, but normally simple problems like this are simple answers, so don't let it frustrate you..
Anyways the few broncos that i have worked on, the ground cable from the top post of the battery runs to the block but about half way down the cable insulation is peeled back an has a clamp that is attached to the frame before it bolted to the block. That was a weak spot on one of the trucks and a **** poor way to run any wire, let alone a major ground
The 88 I'm working on now has 9 ground straps, which is amazing cause I've never seen any vehicle I have ever worked on with so many straps... engine block to firewall, engine block to Cowl, Firewall to hood, Radiator core support to frame, second body frame mount on the left side front to the body, second body frame mount on the right side front to the body, The front left side gas tank to frame rail, The right rear body frame mount to body... I think there was one, i just can't think of it at the moment...
If after checking everything and your still puzzled... Break it down to just the direct ground circuits... starting in the engine compartment, go to any wire that is directly attached to the body or frame with a piece of sandpaper unbolt each wire and scuff it clean & clean around the contact area on the body, smear a small amount of Dielectric Grease and re-tighten it back together. Don't forget the ones on the Radiator core support because if i was a gambling man, those would be the first i would look at besides the ones on the fender.
Good luck and keep us updated...
I know a guy once who was having light problems in an international scout & every time he hit his brakes all the lights would go out or flicker, etc. So one day at this IH wrench a thon, I showed up late & he had 6 guys pulling all his lights out. I mean everything was just hanging and dangling out of his scout, including his steering column, trying to figure out what was wrong... I asked him if he ever had good brake lights & he said yes but after changing the bulb, his lights starting doing this... so he showed me which one, well it turned out he was able to fit a 156 into a 157 and was grounding out all his lights every time he hit the brakes... Lol not to say this is the case here, but normally simple problems like this are simple answers, so don't let it frustrate you..
Anyways the few broncos that i have worked on, the ground cable from the top post of the battery runs to the block but about half way down the cable insulation is peeled back an has a clamp that is attached to the frame before it bolted to the block. That was a weak spot on one of the trucks and a **** poor way to run any wire, let alone a major ground
The 88 I'm working on now has 9 ground straps, which is amazing cause I've never seen any vehicle I have ever worked on with so many straps... engine block to firewall, engine block to Cowl, Firewall to hood, Radiator core support to frame, second body frame mount on the left side front to the body, second body frame mount on the right side front to the body, The front left side gas tank to frame rail, The right rear body frame mount to body... I think there was one, i just can't think of it at the moment...
If after checking everything and your still puzzled... Break it down to just the direct ground circuits... starting in the engine compartment, go to any wire that is directly attached to the body or frame with a piece of sandpaper unbolt each wire and scuff it clean & clean around the contact area on the body, smear a small amount of Dielectric Grease and re-tighten it back together. Don't forget the ones on the Radiator core support because if i was a gambling man, those would be the first i would look at besides the ones on the fender.
Good luck and keep us updated...
Last edited by a moderator:
yo,
One possibility that has been confirmed by other Bronco owners in past few years after I posted this;
Headlight Switch Fires, Part Number SW-2103: "...Over the past two years, this office has experienced fires caused by another potential problem in Ford vehicles. The problem exists within the dimmer portion of the headlight switch in Ford vehicles. The light switch involved is a Model SW-2103. These are the pull out type headlight switches usually located in the lower left corner of the front dash of Ford vehicles. The headlight portion of the switch has two pullout positions, the first for parking lights only, and fully out for headlights and parking lights. The shaft of this pull-out light switch can be turned clockwise and counterclockwise which activates a dimmer switch, lowering and raising the intensity of the lighting in the instrument panels respectively. Fully rotating the shaft counterclockwise past a notch activates the interior lights within the vehicles.
The potential problem exists within the dimmer portion of this switch. The dimmer mechanism consists of a metallic resistive coil set inside a ceramic disc positioned over the shaft of the switch. The coil is exposed on its front side away from the passenger compartment. The front side of the coil passes across a contact permitting a current to flow through a certain portion of the coil when the switch is pulled our in its first or second positions. The greater amount of coil through which the current is permitted to pass (clockwise most position) creates the greatest resistance and therefore dims the dash lighting to its lowest intensity. The opposite position provides greatest intensity. Through our investigations, we have found that the coil can fail owing to wear and/or possible material defects or damage. A fractured coil can maneuver itself free of the ceramic disc permitting it to come in contact with the metal bracket which mounts and grounds the switch to the vehicle.
MIESK5 Note; This could cause a high current drain that causes lower batty voltage thereby the fuel pump relay coil does not sufficient power to close contacts to feed voltage to Pump. Turning off Head Lights gives more voltage back to relay coil thus closing contacts and providing power to pump.
low or no power reaching the fuel pump. Start testing at the fuel pump relay. The relay must respond to the EEC and the relay contacts must be a low resistance path for fuel pump power.
check relay Voltage at pump power terminal; must be within .5v of battery power
Check battery voltage w/head lights ON w/engine off.
do same eng on and then watch voltage when HD Lights are turned on.
.
This is by a good friend here that goes by another handle...
Testing, Ford (Bosch Type); "...Fuel pump relay switches, and other relays are similar to the starter solinoid, in that they make a high amperage connection through a switched low amperage connection. There are two smaller connections, and two larger connections. TO test it, apply 12v to one of the smaller connections, and ground the other smaller connection. (I used to small aligator clipped jumper wries separated by a small piece of cardboard to keep them from shorting against each other.) You should hear it click. Then check for continuity between the two larger connections.Now remove the power from the smaller connections and recheck continuity between the larger connections.With power, one should have continuity, without power it should be an open circuit (no continuity)..."
Source: by Poppy at http://www.fordforumsonline.com/forum/electrical-lighting/144-howto-check-relay.html
When this occurs, a current can flow through a portion of the coil creating high temperatures melting the metal material of the coil and possibly igniting surrounding combustibles. This mechanism has been observed in three separate incidents by this office. Two of these resulted in a fire. The mechanism is precipitated by wear and/or defect in the coil mechanism. If the former is true, we expect there will be an increase in fires caused through this mechanism given an increase in service time. To this date the problem appears to be somewhat limited. However, this particular light switch has been utilized in numerous Ford vehicles. Therefore, a small increase in failure rate owing to age and wear could result in a significant increase in fire losses. The SW-2103 Light Switch Assembly discussed above is reportedly installed in the following Ford vehicles: 1986 -1997 F100, F150, F300; 1990-1994 Explorer; 1987-1994 Ranger; 1987-1990 Bronco II; 1992-1997 Aerostar..." Source: by http://waltersforensic.com/articles/fire_investigation/vol6-no3.htm
Miesk5 NOTE: a shop or PO could have installed this PN in other model year Broncos, see the Ford info below in the Buyer's Guide Results by FORD: Part Number: SW2103 Description: Headlight Switch, Manufacturer: Motorcraft. Years: 1990-1994 Applications: 535: 1992-1994 Bronco; 1990 Bronco II; 1990 E-150 Econoline; 1990 E-250; 1990 E-350; 1990 ******; 1991-1994 Explorer; 1992-1994 F Super Duty; 1992-1994 F-150; 1992-1994 F-250; 1992-1994 F-350; 1990-1994 F53; 1990-1994 F59; 1990-1994 Ranger
Another issue could be the grounds at passenger side fender apron next to battery
Fuel pump relay or battery power feed was open (wiggle power connections while running and check for stall)
One possibility that has been confirmed by other Bronco owners in past few years after I posted this;
Headlight Switch Fires, Part Number SW-2103: "...Over the past two years, this office has experienced fires caused by another potential problem in Ford vehicles. The problem exists within the dimmer portion of the headlight switch in Ford vehicles. The light switch involved is a Model SW-2103. These are the pull out type headlight switches usually located in the lower left corner of the front dash of Ford vehicles. The headlight portion of the switch has two pullout positions, the first for parking lights only, and fully out for headlights and parking lights. The shaft of this pull-out light switch can be turned clockwise and counterclockwise which activates a dimmer switch, lowering and raising the intensity of the lighting in the instrument panels respectively. Fully rotating the shaft counterclockwise past a notch activates the interior lights within the vehicles.
The potential problem exists within the dimmer portion of this switch. The dimmer mechanism consists of a metallic resistive coil set inside a ceramic disc positioned over the shaft of the switch. The coil is exposed on its front side away from the passenger compartment. The front side of the coil passes across a contact permitting a current to flow through a certain portion of the coil when the switch is pulled our in its first or second positions. The greater amount of coil through which the current is permitted to pass (clockwise most position) creates the greatest resistance and therefore dims the dash lighting to its lowest intensity. The opposite position provides greatest intensity. Through our investigations, we have found that the coil can fail owing to wear and/or possible material defects or damage. A fractured coil can maneuver itself free of the ceramic disc permitting it to come in contact with the metal bracket which mounts and grounds the switch to the vehicle.
MIESK5 Note; This could cause a high current drain that causes lower batty voltage thereby the fuel pump relay coil does not sufficient power to close contacts to feed voltage to Pump. Turning off Head Lights gives more voltage back to relay coil thus closing contacts and providing power to pump.
low or no power reaching the fuel pump. Start testing at the fuel pump relay. The relay must respond to the EEC and the relay contacts must be a low resistance path for fuel pump power.
check relay Voltage at pump power terminal; must be within .5v of battery power
Check battery voltage w/head lights ON w/engine off.
do same eng on and then watch voltage when HD Lights are turned on.
.
This is by a good friend here that goes by another handle...
Testing, Ford (Bosch Type); "...Fuel pump relay switches, and other relays are similar to the starter solinoid, in that they make a high amperage connection through a switched low amperage connection. There are two smaller connections, and two larger connections. TO test it, apply 12v to one of the smaller connections, and ground the other smaller connection. (I used to small aligator clipped jumper wries separated by a small piece of cardboard to keep them from shorting against each other.) You should hear it click. Then check for continuity between the two larger connections.Now remove the power from the smaller connections and recheck continuity between the larger connections.With power, one should have continuity, without power it should be an open circuit (no continuity)..."
Source: by Poppy at http://www.fordforumsonline.com/forum/electrical-lighting/144-howto-check-relay.html
When this occurs, a current can flow through a portion of the coil creating high temperatures melting the metal material of the coil and possibly igniting surrounding combustibles. This mechanism has been observed in three separate incidents by this office. Two of these resulted in a fire. The mechanism is precipitated by wear and/or defect in the coil mechanism. If the former is true, we expect there will be an increase in fires caused through this mechanism given an increase in service time. To this date the problem appears to be somewhat limited. However, this particular light switch has been utilized in numerous Ford vehicles. Therefore, a small increase in failure rate owing to age and wear could result in a significant increase in fire losses. The SW-2103 Light Switch Assembly discussed above is reportedly installed in the following Ford vehicles: 1986 -1997 F100, F150, F300; 1990-1994 Explorer; 1987-1994 Ranger; 1987-1990 Bronco II; 1992-1997 Aerostar..." Source: by http://waltersforensic.com/articles/fire_investigation/vol6-no3.htm
Miesk5 NOTE: a shop or PO could have installed this PN in other model year Broncos, see the Ford info below in the Buyer's Guide Results by FORD: Part Number: SW2103 Description: Headlight Switch, Manufacturer: Motorcraft. Years: 1990-1994 Applications: 535: 1992-1994 Bronco; 1990 Bronco II; 1990 E-150 Econoline; 1990 E-250; 1990 E-350; 1990 ******; 1991-1994 Explorer; 1992-1994 F Super Duty; 1992-1994 F-150; 1992-1994 F-250; 1992-1994 F-350; 1990-1994 F53; 1990-1994 F59; 1990-1994 Ranger
Another issue could be the grounds at passenger side fender apron next to battery
Fuel pump relay or battery power feed was open (wiggle power connections while running and check for stall)
devildog95
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great write up guys .I was just flipping through your pages looking where the headlight ground is located an came upon this
