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Back up lights wire gauge?

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Old Dec 1, 2007 | 10:00 AM
  #1  
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Default Back up lights wire gauge?

O.K., I've got the WSM pdf's, all billion pages of them. How do I find what gauge wire is used for a particular line? I want to run higher watt bulbs in my back up lights (long driveway, have to back down it) but don't know if the wires can handle the amps. Thanks.

Don
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Old Dec 1, 2007 | 10:14 AM
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The backup lamps should be 21W each - just like the brake lights.

They are designed for this - do you really need more than that?

If you upgrade the wires - you need to upgrade the whole circuit... fuse, relay etc... Not sure tye lampholders are good for any more that 21W anyway...?

If someone put 5W bulbs in there then thats an easy fix.

You'll need to tell us year for info more specific to your car.

Alan
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Old Dec 1, 2007 | 11:02 AM
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Hi Alan,
It's an early '86. Guess my eyes are just getting old, I'm 51 and I sure can't see as well in the dark as I used to when I was 18, especially backing up with these little mirrors (used to the big ones on the side of my bronco). 21 watt bulbs are fine for parking in the city; backing up in the pitch black, I'd like a little more. I'm sure there are higher watt bulbs out there, I just want to know how high I can go. And until I become a paid member (soon, soon) I'll have to come up with a home made 'sig'.

Don
New Jersey
'86 928 Meteor Metallic
1990 Bronco black
1978 Yamaha XS11 Silver
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Old Dec 1, 2007 | 01:10 PM
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Window tinting doesn't help with your problem.

You can buy 50 watt zenon bulbs for 1156 sockets. I've seen these online and at the local PepBoys. That should work, however if they run too long, they will melt your lenses and wires, assuming you boost the fuse size.

The WSM wiring diagrams give the wire sizes, you just need to look. The numbers are usually located near the color identifiers. They are metric, in crossection (mm squared), so not in typical gage sizes you typically see.
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Old Dec 1, 2007 | 01:54 PM
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I always thought that the back up lights on our cars were bright enough.

However, my back up lights on my Euro don't even work. I checked the bulbs and they are OK. I haven't run down the circuit yet, but anyone have an idea as to what might be the problem?
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Old Dec 1, 2007 | 04:46 PM
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I'd clean up the existing sockets first. They do get corrosion in them which can cut down light output. I'd also replace the bulbs with ones that are properly sized. Check the condition of your lenses as well. You may also want to consider trying LEDs.
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Old Dec 2, 2007 | 03:45 AM
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Cleaned the lenses, cleaned the sockets, have good contact. Don't have any window tinting. Kind of got spoiled by the visability out of the bronco. O.k, looks like metric number is 1.25 (the number next to the color is the gauge?); appears on

http://www.simetric.co.uk/siwire_elect.htm

that it's equivelent to about a gauge 16 wire. OLD gauge 16 wire. 16 gauge is usually good for 10 amps on a 120 volt system, would be able to handle 1200 watts. So, 12 volts into, say, those 2 50 watt halogens (100 watts), would be about 8.5 amps?? Looks like it might work. I have to upgrade the fuse.
Opinions? Has anyone tried this?

Don Bergmann
New Jersey, new owner of an early '86 928 Meteor Metallic, auto
1990 Bronco, black
1978 Yamaha XS11, silver
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Old Dec 2, 2007 | 11:52 AM
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Probably your biggest issue is not with the bulbs but with the fixtures. They are designed to illuminate the area right around the rear of the car - they diffuse raher widely - seems you may need a tighter longer distance throw. Putting 50W bulbs in the housing will damage it quite quickly... I would recommend against it. Finding some exterior mount small metal 50W projection housings and mounting them under the rear - either on the stock reverse circuit (new relay) or on a seperately switched circuit might work better for you needs and have less risk of damaging the wiring/switch/relay.

Alan
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Old Dec 2, 2007 | 02:08 PM
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Hmmm, relay, good idea. Rear is close enough, I can run a 14g wire from the battery with a fusable link, and have a relay connected to the standard wiring. That way I won't melt anything. I don't think I am in danger of melting the housing, as long as the connectors are clean. Max time the bulbs will be lit will only be as long as it takes to back up somewhere, I don't think they will be on long enough to cause a heat problem. Now, if it'll just stop snowing.....
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