Headlight bulbs-SOLVED!, How to test |
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Headlight bulbs-SOLVED!, How to test |
HalfMoon |
Aug 1 2014, 09:48 PM
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#1
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Senior Member Group: Members Posts: 828 Joined: 13-November 12 From: Shenandoah Junction, WV Member No.: 15,144 Region Association: MidAtlantic Region |
Lost my right side headlight high beam. I have another headlight bulb lying around (from PO) but have no idea if it's good or not. Since it's a bit of a bith to change bulbs on our little 914's on a maybe, I thought I'd ask if anyone knows how to test a unmounted headlight bulb. I have an ohm meter and I also have a continuity tester.
Thanks in advance David |
Dtjaden |
Aug 2 2014, 08:51 AM
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#2
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Member Group: Members Posts: 232 Joined: 25-May 13 From: Morgan Hill, CA Member No.: 15,915 Region Association: Northern California |
Looking at the bulb from the back there are 3 connectors, left right and top. The left connector is the common and there should be continuity between that connector and the other two. The right connector is the low beam and the top connector is the high beam.
Using your ohm meter on a low scale you should get a value of just a a few ohms between the left connector and the right connector and between the left connector and the top connector. If you get no value between those connections the bulb is bad. |
HalfMoon |
Aug 4 2014, 01:53 PM
Post
#3
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Senior Member Group: Members Posts: 828 Joined: 13-November 12 From: Shenandoah Junction, WV Member No.: 15,144 Region Association: MidAtlantic Region |
Looking at the bulb from the back there are 3 connectors, left right and top. The left connector is the common and there should be continuity between that connector and the other two. The right connector is the low beam and the top connector is the high beam. Using your ohm meter on a low scale you should get a value of just a a few ohms between the left connector and the right connector and between the left connector and the top connector. If you get no value between those connections the bulb is bad. Rats! I get continuity on the bulb that was in the car and my spare, and both (with my ohm meter set at 2k) give me values of .007. I reckon both bulbs are good and the next step is to test the socket with a test light (switched on with the headlight motor relay removed). I suspect a headlight switch :-( Thanks for the good test advice :-) |
HalfMoon |
Aug 4 2014, 02:06 PM
Post
#4
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Senior Member Group: Members Posts: 828 Joined: 13-November 12 From: Shenandoah Junction, WV Member No.: 15,144 Region Association: MidAtlantic Region |
Looking at the bulb from the back there are 3 connectors, left right and top. The left connector is the common and there should be continuity between that connector and the other two. The right connector is the low beam and the top connector is the high beam. Using your ohm meter on a low scale you should get a value of just a a few ohms between the left connector and the right connector and between the left connector and the top connector. If you get no value between those connections the bulb is bad. Rats! I get continuity on the bulb that was in the car and my spare, and both (with my ohm meter set at 2k) give me values of .007. I reckon both bulbs are good and the next step is to test the socket with a test light (switched on with the headlight motor relay removed). I suspect a headlight switch :-( Thanks for the good test advice :-) Poop. As I suspected the top connector won't light up a test light with the headlights switched on in the high position (motor relay out of course). Now I get to start looking at other stuff :-( |
HalfMoon |
Aug 4 2014, 02:20 PM
Post
#5
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Senior Member Group: Members Posts: 828 Joined: 13-November 12 From: Shenandoah Junction, WV Member No.: 15,144 Region Association: MidAtlantic Region |
Looking at the bulb from the back there are 3 connectors, left right and top. The left connector is the common and there should be continuity between that connector and the other two. The right connector is the low beam and the top connector is the high beam. Using your ohm meter on a low scale you should get a value of just a a few ohms between the left connector and the right connector and between the left connector and the top connector. If you get no value between those connections the bulb is bad. Rats! I get continuity on the bulb that was in the car and my spare, and both (with my ohm meter set at 2k) give me values of .007. I reckon both bulbs are good and the next step is to test the socket with a test light (switched on with the headlight motor relay removed). I suspect a headlight switch :-( Thanks for the good test advice :-) Poop. As I suspected the top connector won't light up a test light with the headlights switched on in the high position (motor relay out of course). Now I get to start looking at other stuff :-( Demmit! Fuse is good. I wonder if a relay gone south could make the right side highbeam not work? Still suspecting the switch (IMG:style_emoticons/default/sad.gif) |
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