I didn't even know what it was until last night but when I swapped the AC wiring harness in the front compartment, a trunk light came with it. Mine didn't have a bulb in it so I just thought some other wiring harness plugged into it. Well I tried the dash bulbs before researching what it actually took. Those didn't work in there. I decided to see if I was getting any voltage before I bought a bulb but that test was negative.
I get continuity between the contacts inside the connector. I don't have continuity from either contact to ground. My AJAR light comes on with the hood raised and the key on. No volts with the key on.
Any suggestions on what the problem might be?
------------------ Jonathan 1987 Notchie - recovering from surgery I'm not a mechanic but I play one in my garage - me Power tends to corrupt, and absolute power corrupts absolutely. - Lord Acton Those who hammer their guns into plows will plow for those who do not. - Thomas Jefferson The tree of liberty must be refreshed from time to time, with the blood of patriots and tyrants. - Thomas Jefferson
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01:39 PM
PFF
System Bot
fierosound Member
Posts: 15253 From: Calgary, Canada Registered: Nov 1999
The front trunk light only comes on when the hood is up AND the headlight switch has the park lights on. Just GM's "idea" for some reason.
All I can think of is that the hood switch sometimes corrodes, and you'd have an "always on" front trunk light killing your battery - and because you'd never know, you'd be totally mystified trying to find the source of your battery drain.
It still seems odd to me that there is continuity between the two contacts inside the socket.
Jonathan
Continuity doesn't mean anything unless you know the design of the circuit. Without voltage you won't get light even if there is a complete circuit. And it depends on what the resistance is...there is a wide range between infinite resistance and zero ohms.
You get continuity (not zero ohms) because when the hood is up, one side of the underhood socket is grounded straight to ground through the switch, and the other side is grounded through the cigar lighter light bulb, and the console ashtray light bulbs, which are on the same circuit. In other words, there is a ground loop through those other light bulbs so while you may be measuring continuity between the two socket contacts, you're actually measuring the resistance of the three other light bulbs in parallel, to ground.
To test this out, while measuring the continuity between the two underhood socket contacts, just press on the underhood switch... it should break the continuity and result in infinite ohms. Alternatively, you can remove the three other light bulbs and you'll see the same result (provided the headlight switch is in the off position... it gets more complicated if the switch is on since the transistorized remote instrument panel dimmer gets energized and then provides yet another path to ground).
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05:52 PM
Boostdreamer Member
Posts: 7175 From: Kingsport, Tennessee USA Registered: Jun 2007
No, it was just to explain why you can read continuity on the socket. Your reading the 'other' bulbs continuity
A better test might be to turn the parking lights on, and then read for voltage. Rotate the "hood ajar" switch if the bulb doesn't come on right away - it might be dirty.
[This message has been edited by phonedawgz (edited 04-04-2010).]
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08:44 PM
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
You get continuity (not zero ohms) because when the hood is up, one side of the underhood socket is grounded straight to ground through the switch, and the other side is grounded through the cigar lighter light bulb, and the console ashtray light bulbs, which are on the same circuit.
Thanks Blooz...you explained that far better than I did. I was going to award you a "+" for that, but it appears I already have. Oh well.
