bryonbush 85 Report post Posted December 22, 2015 last month my alternator and voltage regulator went bad so replaced both. few weeks later i was driving down the road at night since the new parts were installed and switched to the high beams. got the flicker then the lights died but low beams worked fine. asked on the forums and everyone said it was a switch. yesterday i put in a new switch and new scott drake halogen bulbs. tonight while driving, got the flicker then lost all lights. so whats going on all of a sudden? is it the voltage reg maybe throwing issues? one thing that does have me curious is when i swapped out the motors the PO didnt have a ground wire attached to the back of the Alt. So i never hooked it up either. when i did the alt swap, we put it on. would this be a possible issue? Quote Share this post Link to post Share on other sites
shaun071 62 Report post Posted December 22, 2015 Are you getting a click from the headlight switch circuit breaker then the lights go out? Mine was doing that after I installed halogen high beams and I had wired the lights backwards. Reversed the wiring and it worked fine. Quote Share this post Link to post Share on other sites
bryonbush 85 Report post Posted December 22, 2015 no notable clicking noise. the headlight kit isnt anything special or high powered. the problem started with the old bulbs so its not the new set. the headlight and dimmer switches are all new. Quote Share this post Link to post Share on other sites
ray1970 88 Report post Posted December 22, 2015 Ray hear. After replacing far to many headlamp switches in my 1970 I finally went with the relay setup...problem solved(for me) Headlamps going out at night was not a good thing...sometimes they would go on and off a bitt before the final black out. Cars would pull over thinking I wanted to pass....what I really needed was to follow there tail lights to get home... Aging copper wires in the 45 year old harness will create a lot of resistants' over time kicking out the thermo switch built into the headlamp switch....The after market ones appear to be way more sensitive about this.. Ray. Quote Share this post Link to post Share on other sites
machm1970 180 Report post Posted December 22, 2015 I don't remember which vendor it is (NPD maybe?) offers a heavier duty headlight switch that they recommend when using aftermarker headlights. Matt 1 Papa John reacted to this Quote Share this post Link to post Share on other sites
SA69mach 39 Report post Posted December 26, 2015 The headlight wiring goes through the dimmer switch, so perhaps check that as well. it should switch through a full 12V when operated. Sometimes the wiring is worn through or intermittently grounding. Just another thing to check, or replace...... Quote Share this post Link to post Share on other sites
Rsanter 152 Report post Posted December 26, 2015 What switch did you replace? I have seen the dimmer switch on the floor fail and I have seen the headlamp switch in the dash fail Bob Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted December 26, 2015 Running halogens through the headlight switch without a relay is asking for trouble (flickering). I also concur with the dimmer switch being bad as a possible cause. Finally, corrosion within the wiring (connectors, pins, wires themselves) adds resistance and increases current load, which causes the headlight circuit breaker to break on/off/on/off (i.e. flickering). Quote Share this post Link to post Share on other sites
bryonbush 85 Report post Posted December 26, 2015 the flickering issue started before I put in these new bulbs. And the Halogens arnt the high tech H4 ones, just basic Scott Drake's which draws no more power than the others according to their specs. I replaced the headlight and the dimmer switch. the down side is i dont know if it was the new headlight switch or putting the new alt/volt regulator on that started the issue. What i do find odd is it seems like the two outside bulbs are running brights now all the time. when i kick the "brights" on, the lights actually get darker with all 4 on before i start getting the issues. This has me thinking that the switch is goofed in some way. I did order a relay kit as they were on sale, but would like to get this figured out still. Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted December 26, 2015 I read somewhere that 90% of electrical problems are grounding related. Quote Share this post Link to post Share on other sites
7TCatvert 24 Report post Posted December 26, 2015 Not suggesting this is the problem....but the new headlight switches are junk....I ended up buying used one.... Quote Share this post Link to post Share on other sites
ray1970 88 Report post Posted December 26, 2015 Ray here. Rambling...As a LONG time tech (Or what ever they call us)Most electrical parts replacement are more from poor testing or none..(Did not fix the problem)Yes grounds can be a problem and should always be looked at first.Most of what I see is the OEM or replacement parts not up to the task your asking or it was just crap in the first place...Ray. Quote Share this post Link to post Share on other sites
RobotMan 264 Report post Posted February 21, 2016 Just tried to adjust my headlights on my sons car and the lights started fading and flickering in an out when the bright lights turned on. So guess I have the problems described in this post. I have new harnesses, switches, regulators, and bulbs. Guess I need to go ahead and install the relay kit. Which kit and where have you guys had success with. I would like one that does not require cutting the existing factory harnesses. Thanks Rick Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted February 21, 2016 RCCI has some slick solutions for this: http://www.rccinnovations.com/index.php?show=menu-mustang-all#relays No cutting of the existing harness. Check it out! Quote Share this post Link to post Share on other sites
LiLMike 42 Report post Posted February 21, 2016 I had the same problem with a 70 Mach1 years ago only all my lights flickered and went out. It turned out to be a faulty connector going to the dimmer switch. Quote Share this post Link to post Share on other sites
RobotMan 264 Report post Posted March 21, 2016 RCCI has some slick solutions for this: http://www.rccinnovations.com/index.php?show=menu-mustang-all#relays No cutting of the existing harness. Check it out! I purchased one of his relay kits. Seems to have fixed the problem. Very clean install. Thanks for the tip. Rick Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted March 21, 2016 So Rick, did you add the relays for aftermarket head lights? Quote Share this post Link to post Share on other sites
RobotMan 264 Report post Posted March 21, 2016 Yes I suspect the combo of after market headlights (50 Watts each) and an aftermarket headlight switch was causing the problem. I purchased the dual relay box option for safety. The headlights seem to work fine now. The brights would not stay on for more than about 10 seconds before. Was very clean and did not have to cut harnesses. Did have to mount 2 relay boxes and a circuit breaker. Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted March 21, 2016 Thanks. Quote Share this post Link to post Share on other sites
