flickering headlights/dash...??

bruzrs78 · 11-10-2012, 12:20 PM

working on my first f.s. 78. i have put a new alt. in and now i have a headlight flckering issue. dash and domelight as well. i have checked grounds and have had the alt. bench checked and was fine. again this is my first older ford i have worked on, so any advise would b awesome.... thanx!

**88Bronco300** · 11-10-2012, 07:08 PM

This happened on my '88. Turns out the headlight switch was bad. May not be your issue but something to check out.

**rhauf** · 11-10-2012, 08:13 PM

flickering as in, slightly brighter and dimmer? (this would suggest a jumpy voltage regulator. use a volt meter to see if voltage is inconsistent at battery while engine is running)

or, flickering as in, turning off momentarily now and then/flickering off. this would likely be the headlight switch, headlight switch plug, fusable links, or some other connection. turn them on for a bit and feel for a hot connection. heat = resistance (which means problem found)

bruzrs78 · 11-11-2012, 10:10 PM

yes i have tried a test on the battery and voltage does jump around or (not consistant) while engine is idling. i noticed at nite in driveway the brake lights flicker also. so i will try my luck with a new voltage regulator. i had already tried eveything that was suggested in that trouble shooting link in this thread. thats y i went alittle further on my own last nite. thanx for your help... it is greatly appreciated.

kentucky4x4 · 11-12-2012, 12:43 AM

my 88 done the same thing. ended up being the headlight switch like said above.

Mstroker · 11-12-2012, 11:45 AM

My buddy has an F350 with a 460 in it that keeps murding his head light switches, my money is that yours is bad too.

If it turns out that it's not the switch I would start checking grounds

**AbandonedBronco** · 11-12-2012, 12:35 PM

I've had this happen twice.

First time was the headlight switch.
Second time was the high beam switch on the floor.

bruzrs78 · 11-12-2012, 08:55 PM

well, now i have a backup voltage regulator. cuz that was not it... yeah i am going to replace the headlight switch and the floor dimmer.. i have gone through the grounds. pulled apart and cleaned off and all that good stuff. im hoping this not going to be one of those electrical freak shows....

**JScatt** · 11-12-2012, 09:19 PM

When you say flicker I'm assuming you mean split second lights are on/off. Does it get worse/better when you hit bumps?

**GetBent4x4** · 11-12-2012, 09:25 PM

Melted power wire plastic holder on headlight switch harness.

bruzrs78 · 11-12-2012, 09:57 PM

no it does not get worse running over bumps. it is consistant in high and low beam. and or when dome light is on. also noticed the other night just appling the brakes, and the brakelights do the same. that is brake lights alone.

bruzrs78 · 11-23-2012, 05:04 PM

well, well,well... lol! imagine that found and fixed the issue... come to find out there was a bad connection with the wiring harness to the voltage regulator. went out and got a pigtail 4plug harness,spliced the wires and solder together.... and no more "flickering"... man, what a pain it was. and comes down to something so damn simple... thanx for all of your input. it was appreciated!!!!!!

**AbandonedBronco** · 11-24-2012, 12:40 PM

Glad you found it! And thanks for posting up what the issue was. :)
Easy fixes are the best.

11-10-2012, 12:20 PM	#1
bruzrs78 Registered User Join Date: Sep 2012 Location: So. Central Idaho (magic valley) Posts: 13 iTrader: (0) Bronco Info: mostly stock (for now) 78 fullsize. has a 3"bl. w/35s. 351m 4bbl. edlebrock intake	flickering headlights/dash...?? working on my first f.s. 78. i have put a new alt. in and now i have a headlight flckering issue. dash and domelight as well. i have checked grounds and have had the alt. bench checked and was fine. again this is my first older ford i have worked on, so any advise would b awesome.... thanx!

11-10-2012, 08:13 PM	#3
rhauf FSM Lifetime Join Date: Jul 2007 Posts: 4,781 iTrader: (3) Bronco Info: 82 bronco 408w 4" lift 35's, 88 bronco 351w all stock on 31s	flickering as in, slightly brighter and dimmer? (this would suggest a jumpy voltage regulator. use a volt meter to see if voltage is inconsistent at battery while engine is running) or, flickering as in, turning off momentarily now and then/flickering off. this would likely be the headlight switch, headlight switch plug, fusable links, or some other connection. turn them on for a bit and feel for a hot connection. heat = resistance (which means problem found) __________________ -Ryan Check out my youtube page. Many bronco videos. http://www.youtube.com/user/rhauf1

11-12-2012, 11:45 AM	#6
Mstroker Registered User Join Date: Oct 2012 Location: Galesburg area, Illinois Posts: 6 iTrader: (0) Bronco Info: 1989 F150	My buddy has an F350 with a 460 in it that keeps murding his head light switches, my money is that yours is bad too. If it turns out that it's not the switch I would start checking grounds __________________ 1989 F150, 302, auto, 4x4, 9in rear swap 3.73 ratios Maxxis big horn 33's on american racing wheels Decked out with Cb's an police scanner bone stock other wise Soon to be 302 with, forged internals for about 300 hp, and a 125/150 shot of the spray!!

11-12-2012, 12:35 PM	#7
AbandonedBronco Big Six Join Date: Feb 2006 Location: Boise, ID Posts: 2,041 iTrader: (1) Bronco Info: 1981 300ci 6cyl w/4bbl conversion. 4spd manual	I've had this happen twice. First time was the headlight switch. Second time was the high beam switch on the floor. __________________ 1981 & 1984. Both w/ 300 I6. Holley 600 4bbls. 31x10.5" tires. NP-435 trans. 2.5" Exhaust. Supermotors Pics

11-12-2012, 09:19 PM	#9
JScatt Fullsize Member Join Date: Jan 2010 Location: SoCal Posts: 2,044 iTrader: (2) Bronco Info: 1995 XLT 351W, 2.5 R/C Lift,4.10's..much more to come	When you say flicker I'm assuming you mean split second lights are on/off. Does it get worse/better when you hit bumps? __________________ No bum that can't speak poifect English oughta stay in this country...oughta be de-exported the hell outta here!" -Archie Bunker bron·co/ˈbräNGkō/ Noun: A wild or half-tamed horse, esp. of the western US.

11-10-2012, 07:08 PM	#2
88Bronco300 She likes my Join Date: Jan 2012 Location: Hammonton, South Jersey Posts: 261 iTrader: (0) Bronco Info: '88 XLT with 4.9. 10" of lift on 40's. Saving for sas!	This happened on my '88. Turns out the headlight switch was bad. May not be your issue but something to check out.

11-11-2012, 10:10 PM	#4
bruzrs78 Registered User Join Date: Sep 2012 Location: So. Central Idaho (magic valley) Posts: 13 iTrader: (0) Bronco Info: mostly stock (for now) 78 fullsize. has a 3"bl. w/35s. 351m 4bbl. edlebrock intake	yes i have tried a test on the battery and voltage does jump around or (not consistant) while engine is idling. i noticed at nite in driveway the brake lights flicker also. so i will try my luck with a new voltage regulator. i had already tried eveything that was suggested in that trouble shooting link in this thread. thats y i went alittle further on my own last nite. thanx for your help... it is greatly appreciated.

11-12-2012, 12:43 AM	#5
kentucky4x4 Registered User Join Date: Oct 2012 Posts: 168 iTrader: (0)	my 88 done the same thing. ended up being the headlight switch like said above.

11-12-2012, 08:55 PM	#8
bruzrs78 Registered User Join Date: Sep 2012 Location: So. Central Idaho (magic valley) Posts: 13 iTrader: (0) Bronco Info: mostly stock (for now) 78 fullsize. has a 3"bl. w/35s. 351m 4bbl. edlebrock intake	well, now i have a backup voltage regulator. cuz that was not it... yeah i am going to replace the headlight switch and the floor dimmer.. i have gone through the grounds. pulled apart and cleaned off and all that good stuff. im hoping this not going to be one of those electrical freak shows....

11-12-2012, 09:25 PM	#10
GetBent4x4 Fullsize Member Join Date: Jun 2010 Location: Plano, TX Posts: 3,137 iTrader: (1) Bronco Info: Brick Nose on 15x10s/32s with leveling coils	Melted power wire plastic holder on headlight switch harness.

11-12-2012, 09:57 PM	#11
bruzrs78 Registered User Join Date: Sep 2012 Location: So. Central Idaho (magic valley) Posts: 13 iTrader: (0) Bronco Info: mostly stock (for now) 78 fullsize. has a 3"bl. w/35s. 351m 4bbl. edlebrock intake	no it does not get worse running over bumps. it is consistant in high and low beam. and or when dome light is on. also noticed the other night just appling the brakes, and the brakelights do the same. that is brake lights alone.

11-23-2012, 05:04 PM	#12
bruzrs78 Registered User Join Date: Sep 2012 Location: So. Central Idaho (magic valley) Posts: 13 iTrader: (0) Bronco Info: mostly stock (for now) 78 fullsize. has a 3"bl. w/35s. 351m 4bbl. edlebrock intake	well, well,well... lol! imagine that found and fixed the issue... come to find out there was a bad connection with the wiring harness to the voltage regulator. went out and got a pigtail 4plug harness,spliced the wires and solder together.... and no more "flickering"... man, what a pain it was. and comes down to something so damn simple... thanx for all of your input. it was appreciated!!!!!!

11-24-2012, 12:40 PM	#13
AbandonedBronco Big Six Join Date: Feb 2006 Location: Boise, ID Posts: 2,041 iTrader: (1) Bronco Info: 1981 300ci 6cyl w/4bbl conversion. 4spd manual	Glad you found it! And thanks for posting up what the issue was. :) Easy fixes are the best. __________________ 1981 & 1984. Both w/ 300 I6. Holley 600 4bbls. 31x10.5" tires. NP-435 trans. 2.5" Exhaust. Supermotors Pics

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