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Electrical Gremlins. Bad Alt? Grounds? Ideas?


jrhone

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1 hour ago, Hans said:

why would they ground the relay through the bulb?

Hans,

Not a dumb question!  

This is just a clever way of turning the low beams OFF when the high beams are ON. The #85 tab on the low-beam relay is grounded through the high-beam light filament, so when the #86 tab is energized by the ignition switch, and the headlight switch is ON, the current flows from the #87 tab to fuses #9 & #10 to light the low beams. When the high beams are turn on, 12v is sent to the low-beam relay tab #85, which cuts off the ground path, turning off the low-beams.  

Because the headlight current flows through the ignition switch and the head light and turn signal switches, the circuit designers didn't want to have 2 x 55 watt (low beams) PLUS 2 x 60 watt (high beams) on at the same time.  There are several articles about how to use extra relays and fuses to draw current directly from the  + battery (or +B post on alternator) to utilize higher power bulbs (or having both low and high beams on at the same time). This, however, usually requires an alternator and wiring upgrade as well. 

The LED light is a modern solution to many problems with incandescent bulbs (low output, high current, short life, thick (heavy) wires, beefy relays, etc. 

John

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2 hours ago, Chris_B said:

No. The relay needs ground to operate the solenoid (switch), but only passes +12V to the light. Ground for the headlights is usually local.

I'm just going by the drawing. 

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In the just for sh*ts and giggles department, try getting the car warmed up and run for 10 minutes of so after the headlights return to normal and then park on a slope letting the car sit for a bit and then compression start it and see how the headlights react.

If everybody in the room is thinking the same thing, then someone is not thinking.

 

George S Patton 

Planning the Normandy Break out 1944

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From all of the problems I've been reading about lately with LED's in 02's it seems the 02's factory lighting system is not easily upgraded for LED's, because it was not designed for them. Incandescent bulbs and LED's work differently and are not always interchangeable. Incandescent bulbs have a filament that connects the 2 electrical contacts and doesn't care which way current flows, LED's don't have a filament and are diodes which will only pass current one way.

 

So if you want LED's you should upgrade the wiring system appropriately. This may include the headlight switching system, the flasher/turn signal system, the instrument panel lighting and alternator wiring depending on where you are putting the LED's.

 

It's not a bad idea to update the original 45+ year old wiring that wasn't the best design to begin with and by now has probably become a fire hazard. That and if your upgrading the lights to LED's you are probably not going for originality. So adding a stereo and other electronic accessories will require you too upgrade your alternator and most likely get rid of the original external voltage regulator. And if you're like the rest of us on here you'll notice ten other things that need fixing/upgrading, maybe just stick with the old incandescent bulbs and enjoy your car during the day and not get carried away.....yeah right lol.

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I can't speak for iii, but overall for the headlights you could loose the relays and since they only draw 2.25 amps for both you could drop the wire gauge down to 22g, the turn signals as fitted won't blink with the low draw from the led's you could also drop the wires to 22g, and the alternator will not charge correctly with out a filament bulb in the cluster.  

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If everybody in the room is thinking the same thing, then someone is not thinking.

 

George S Patton 

Planning the Normandy Break out 1944

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1 hour ago, Chris_B said:

How would you suggest that the wiring system be upgraded, and why would the headlight switching system and flasher system need to be upgraded, to use LEDs?

2nd Q 1st:

Because LEDs are not resistors - they are diodes....that means they dont conduct 'backwards' and their 'forward' characteristic is non-linear in the 0-2V range. 

 

Its quite common for Car manufacturers to use the resistor character of incandescent lamps for additional features (here its fail-safe approach to prevent over-current, in some cars its part of the bulb failure diagnostic)

 

1st Q 2nd:

I think you could make LED headlamps work by using relays with SPDT double throw and wiring the dipped beam direct to ground rather than thru the filament... need to sketch a suitable circuit...

'59 Morris Minor, '67 Triumph TR4A, '68 Silver Shadow, '72 2002tii, '73 Jaguar E-Type,

'73 2002tii w/Alpina mods , '74 2002turbo, '85 Alfa Spider, '03 Lotus Elise

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38 minutes ago, dlacey said:

Its quite common for Car manufacturers to use the resistor character of incandescent lamps for additional features (here its fail-safe approach to prevent over-current, in some cars its part of the bulb failure diagnostic)

 

 

Perhaps, but this is not relevant to 02 electrical systems.

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Chris B.

'73 ex-Malaga

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1 hour ago, Son of Marty said:

I can't speak for iii, but overall for the headlights you could loose the relays and since they only draw 2.25 amps for both you could drop the wire gauge down to 22g, the turn signals as fitted won't blink with the low draw from the led's you could also drop the wires to 22g, and the alternator will not charge correctly with out a filament bulb in the cluster.  

Ripping out wires seems like a radical solution to a problem that does not need to be resolved. For turn signals, you can either add resistors into the LED circuit or use an LED compatible turn signal relay. I don't think anyone suggested using an LED for the +D circuit in the alternator (a mistake as  you described).

Chris B.

'73 ex-Malaga

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2 hours ago, Chris_B said:

Ripping out wires seems like a radical solution to a problem that does not need to be resolved. For turn signals, you can either add resistors into the LED circuit or use an LED compatible turn signal relay.

 

True, but you cant use an LED headlamp in the >73 cars that have relays in both Hi & Lo beam circuits for the reasons above... the only option is to 'rip out' /modify a few wires near the relays...or stick with incandescents.

'59 Morris Minor, '67 Triumph TR4A, '68 Silver Shadow, '72 2002tii, '73 Jaguar E-Type,

'73 2002tii w/Alpina mods , '74 2002turbo, '85 Alfa Spider, '03 Lotus Elise

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OK...guys update....

 

I checked the grounds...checked voltage everywhere.

Everything looked good...then I pulled the CRUSTY relay that ran the low beams...swapped it for a newer relay....

 

Problem solved.

Headlights work like stock...just aloft more light.

 

 

 

1976 BMW 2002 Fjord Blue Ireland Stage II • Bilstein Sports • Ireland Headers • Weber 38 • 292 Cam • 9.5:1 Pistons • 123Tune Bluetooth 15" BBS

2016 BMW 535i M Sport

1964 Volvo Amazon Wagon
http://www.project2002.com

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Here are the headlights by the way.  They come with 3 lens options.  Budget, E Code and Hella.  I got the E code lenses.  Unplug the light.  Remove from the light bucket.  Install new light in the light bucket.  Plug in the new light.  Done.  Install was simple.  Aimed so not to blind oncoming traffic.  Color is white.  

 

IMG_1241.jpeg

1976 BMW 2002 Fjord Blue Ireland Stage II • Bilstein Sports • Ireland Headers • Weber 38 • 292 Cam • 9.5:1 Pistons • 123Tune Bluetooth 15" BBS

2016 BMW 535i M Sport

1964 Volvo Amazon Wagon
http://www.project2002.com

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