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C5 under hood light only 8 volts???

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Old Dec 2, 2023 | 03:18 PM
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Default C5 under hood light only 8 volts???

Just tried to install an LED. It was very dim so I tested the voltage and it reads 8 V and then tested back at the battery and it’s definitely 12.2 V. Where should I look first
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Old Dec 2, 2023 | 03:46 PM
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Open and close the hood to make sure the timer circuit has not kicked in. FYI, I tried an underhood LED and it did not work well due to the timer circuit. Did not draw enough current. Good luck.
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Old Dec 2, 2023 | 03:50 PM
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Originally Posted by jcgunn
Open and close the hood to make sure the timer circuit has not kicked in. FYI, I tried an underhood LED and it did not work well due to the timer circuit. Did not draw enough current. Good luck.
what exactly is the timer cycle? Also did open/close no change in brightness. I hooked led direct to battery and it’s really bright??? Why would it have to draw more current? No canbus on 1998 vette
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Old Dec 2, 2023 | 07:57 PM
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Mine is an 03 and the LED never worked right. It would be bright for a minute or two and then dim out. Recycling the hood reset the mercury switch and reset the ten minute timer, LED still dimmed out in a minute or two. The circuit is designed to make sure you can't drain the battery by leaving the hood open, so it turns off after ten? minutes.
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Old Dec 3, 2023 | 11:05 AM
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Originally Posted by wizard0356
Just tried to install an LED. It was very dim so I tested the voltage and it reads 8 V and then tested back at the battery and it’s definitely 12.2 V. Where should I look first
Look at the ground for the bulb...you can use a 12 volt test light connected to B+ to check the ground.
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Old Dec 3, 2023 | 04:10 PM
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Originally Posted by wizard0356
what exactly is the timer cycle? Also did open/close no change in brightness. I hooked led direct to battery and it’s really bright??? Why would it have to draw more current? No canbus on 1998 vette
Timer cycle turns the underhood light off after approx 10(?) minutes...
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Old Dec 4, 2023 | 02:55 AM
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Moved to C5 Tech.
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Old Dec 4, 2023 | 06:54 AM
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Try to measure voltage between ground and fuse 2 on diagram (R1 term on relay) and between ground and P1 on relay)
These voltages shall be equal , but burned contacts in relay 37 can cause voltage drops over relay contacts.
Also check ground G102 and SplicePack 100 for good continuity .



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