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Hey folks, i've got an issue with my headlights. Often when I switch to highbeams I lose my headlights completely. It will also happen randomly while the highbeams are on. Switching back to lowbeams always fixes it instantly. My guess is it's in the switch, and it's starting to get pretty bad (highbeams work maybe %50 of the time)
If it is the switch, is there any hope of rehabbing these 30 year old switches or should I just start looking for a new unit?
read RAD4runner's build thread - ruby. tuesday - in the build section. the switch contacts are likely worn because of factory incorrect wiring flaws. the switch sometimes can be rehabbed, but you need to fix the wiring flaw to prevent it from happening again.
O.P.,
High Beam flash works, correct? That confirms it is the witch contacts.
You can probably rehab the contacts but need to get H4 conversion harness to:
1) Help extend its life.,
2) Eliminate the excessive voltage drop from bad factory wiring. To illustrate how bad the factory wiring is:
Voltage Drop Comparisons:
With Sealed Beam & Engine off
Stock Wiring
Low Beam:
Batt: 12.05V, Across low beam filament (pins 1 & 3): 11.15V
Voltage drop in wiring: 0.9V
volt drop = 7.5% of battery voltage
High Beam:
Batt 11.94, Across high beam filament (pins 2 & 3): 10.07
Volt drop: 15.7% of battery voltage!
After Retrofit / (h4 conversion harness):
Low Beam:
Batt: 12.31V, : Across low beam filament (pins 1 & 3): 12.11V
Volt Drop: 0.2 = 1.6% of Battery voltage
High Beam:
Batt: 12.24V, Across high beam filament (pins 2 & 3): 11.78V
Voltage drop: =0.46V = 3.75% of battery voltage
O.P.,
High Beam flash works, correct? That confirms it is the witch contacts.
You can probably rehab the contacts but need to get H4 conversion harness to:
1) Help extend its life.,
2) Eliminate the excessive voltage drop from bad factory wiring. To illustrate how bad the factory wiring is:
Voltage Drop Comparisons:
With Sealed Beam & Engine off
Stock Wiring
Low Beam:
Batt: 12.05V, Across low beam filament (pins 1 & 3): 11.15V
Voltage drop in wiring: 0.9V
volt drop = 7.5% of battery voltage
High Beam:
Batt 11.94, Across high beam filament (pins 2 & 3): 10.07
Volt drop: 15.7% of battery voltage!
After Retrofit / (h4 conversion harness):
Low Beam:
Batt: 12.31V, : Across low beam filament (pins 1 & 3): 12.11V
Volt Drop: 0.2 = 1.6% of Battery voltage
High Beam:
Batt: 12.24V, Across high beam filament (pins 2 & 3): 11.78V
Voltage drop: =0.46V = 3.75% of battery voltage
Thanks for the info! This explains a lot, I've definitely noticed an improvement the warmer the weather.
Just read through this:
http://www.4crawler.com/4x4/CheapTricks/Headlights.shtml#WiringHarness
And I fear this may be quite a bit beyond my electrical abilities. I drive a 22r and a 12 valve for a reason...
i'm not an electrical wiz, but i used info from RAD and 4crawler to add an h4 headlight harness to my truck. a one to one and a half hour project. it will take longer to remove the headlight switchstalk and disassemble it to clean the contacts. that's a three hour project if you've never done it.
i'm not an electrical wiz, but i used info from RAD and 4crawler to add an h4 headlight harness to my truck. a one to one and a half hour project. it will take longer to remove the headlight switchstalk and disassemble it to clean the contacts. that's a three hour project if you've never done it.
Alright, I suppose I'll give it a shot. What all do I need? I'd love to keep the stock lamps.
Good job, Wallytoo! sweitzerworks,
What Wally made is the alternative to buying "h4 conversion' harness. Personally, I prefer to make things my way than buy from someone I do not trust.
The voltages I posted above merely shows improvement from stock compared to modified wiring that fixes what 4Crawler calls "convoluted wiring". Many people are not aware that this is more essential for the headlight system. Merely "upgrading" to higher wattage bulbs without the "H4 conversion" will subject the switch contacts to worse currents than what yours already saw.
Good job, Wallytoo! sweitzerworks,
What Wally made is the alternative to buying "h4 conversion' harness. Personally, I prefer to make things my way than buy from someone I do not trust.
The voltages I posted above merely shows improvement from stock compared to modified wiring that fixes what 4Crawler calls "convoluted wiring". Many people are not aware that this is more essential for the headlight system. Merely "upgrading" to higher wattage bulbs without the "H4 conversion" will subject the switch contacts to worse currents than what yours already saw.
Yeah I'm definitely trying to fix the wiring. I've owned two other yotas before this one and in BOTH I had to replace the switch, not knowing the origin of the symptoms.
At this point however, I'm a little confused. Am I buying a harness or building a harness? Either way I'm not totally sure what I need :/
Last edited by sweitzerworks; 01-08-2018 at 07:44 PM.
REPEAT: High Beam flash works, correct? That confirms it is the switch contacts. You can probably rehab the contacts but need to get H4 conversion harness to:
1) Help extend its (contact) life.,
2) Eliminate the excessive voltage drop from bad factory wiring. To illustrate how bad the factory wiring is:
Your choice: Make your own H4 conversion harness (see schematic on 4Crawler's website) like Wallytoo did OR buy from online store.
Last edited by RAD4Runner; 01-08-2018 at 07:50 PM.
REPEAT: High Beam flash works, correct? That confirms it is the switch contacts. You can probably rehab the contacts but need to get H4 conversion harness to:
1) Help extend its (contact) life.,
2) Eliminate the excessive voltage drop from bad factory wiring. To illustrate how bad the factory wiring is:
Your choice: Make your own H4 conversion harness (see schematic on 4Crawler's website) like Wallytoo did OR buy from online store.
sweitzer, one thing about using the harness/h4, the dash indicator will become too dim to see in daylight, and be barely bright enough to see when driving at night. 4 crawler has a section on this, but i haven't figured it out yet. although i'd like to have a working indicator, functional switch contacts are more important.
...one thing about using the harness/h4, the dash indicator will become too dim to see in daylight,.... 4 crawler has a section on this, but i haven't figured it out yet....
The reason for dim high-beam indicator is because the high-resistance relay coil now replaces the low resistance of the low-beam filament between pins 1 and 3 (schematic here). A fix would be either:
1) Try replacing the low-beam indicator bulb with LED (Pls let us know if anyone has done this successfully), OR
2) To put a resistance in parallel with that relay coil (from pin1 to pin3). Not sure what value, yet, but I would try the shunt resistor used with LED turn signals (to band-aid hyper-flash).
With fix option #2) when indicator is on, it will run higher than necessary current through low-beam contact in order to keep high-beam indicator off. Not as high as with stock wiring but still unnecessary. The design of the high-beam indicator is another screw-up from engineers trying to be fancy.
What's wrong with simply wiring the high-beam indicator in parallel with high-beams (between pins 1 & 2)?! DUH! This is what I want to do but have no time to trace the wires.
I've got no problem with a dim indicator. I actually taped over the light because it was blinding me on long road trips. I much prefer a cab free of distractions.
01-07-2018, 05:55 PM
