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1979 clock, lighter, courtesy 20 amp fuse

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Old 07-10-2018, 04:41 PM
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79Vette4spd
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Default 1979 clock, lighter, courtesy 20 amp fuse

1979 clock, lighter, courtesy 20 amp fuse works in circuit with key on. Turn key off and clock works. Once you start the car and drive for a while the fuse blows. I do not notice other electrical problems. I am going through the body and chasis electrical troubleshooting in the shop manual but wondered if anybody has had and solved this problem.
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Old 07-10-2018, 05:35 PM
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Matt81
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I'd check the conn action under the cigarette lighter, and the lighter assembly itself. Perhaps while driving along, something shaking loose and grounding itself out.
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Old 07-10-2018, 05:40 PM
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BlackC3vette
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Originally Posted by Matt81 View Post
I'd check the conn action under the cigarette lighter, and the lighter assembly itself. Perhaps while driving along, something shaking loose and grounding itself out.

I can see that happening with my 80 because the connection underneath can short out easily. Take the side panel off and take a look.
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Old 07-10-2018, 07:09 PM
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I agree....the orange wire is grounding out somewhere...and unfortunately...this circuit has a lot being used that w ill need to be checked.

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Old 07-11-2018, 01:29 AM
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KapsSA
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Do you have a power antenna and does it work?
A burned out antenna motor will pop that fuse when the radio gets turned on.
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Old 07-11-2018, 02:09 PM
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79Vette4spd
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Originally Posted by KapsSA View Post
Do you have a power antenna and does it work?
A burned out antenna motor will pop that fuse when the radio gets turned on.
Thanks, My power antenna does not work. Does the power antenna kick on when the key is in accessory position and the radio is turned on? The fuse does not blow until the car is started. I need to take the seat out again to get the side panel off and check the orange wire. Going to take it out for a drive first.
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Old 07-11-2018, 03:48 PM
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KapsSA
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I've come across a few burned out antennas over the years dealing with rebuilding that I've done. Mostly the early79 type aluminum housing units. Including my former 25 mile pace car.
My assumption is a faulty RELAY caused the problem. When you get that side panel off the pass side unplug the connector from the relay and see if the fuse still blows.
It's hard to tell if either style 79 antenna is burned out with it installed. The aluminum housing unit will possibly show some wires melted, you really need to open it up to see if the armature is cooked. The plastic later antenna may show some melting of the housing.
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Old 07-11-2018, 03:49 PM
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Originally Posted by 79Vette4spd View Post
Does the power antenna kick on when the key is in accessory position and the radio is turned on?
Yes, but likely the relay.
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Old 07-11-2018, 06:10 PM
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I unplugged the wires from the relay and that solved the problem. Can I just leave the wires unplugged? Does that mean the power antenna is bad and needs to be replaced or is the relay bad?

Thanks again
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Old 07-12-2018, 02:36 AM
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The relay is probably bad and most likely fried the antenna.
Leave it unplugged if you don't need the antenna operational.
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Old 07-12-2018, 08:24 AM
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I installed this Metra antenna unit last year in my 78 that Reid not originally come with a power antenna but OK had broken the fixed last. Relay is built in, so you should be able to bypass the fried relay.

Metra Link Metra Link
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Old 07-12-2018, 10:15 AM
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Default Orange Wire Circuit:

As "DUB" states this circuit runs a lot of separate items.
I just chased an "erratic courtesy /clock fuse burning condition" on a 1978.

The dome light (between the T-Tops) had been recently assembled wrong.
The clips that hold the Long-Bulb can be snapped into the plastic base 2 different ways.
If either of the crimped wire pig-tails is/ are pointing OUT they can touch the steel-frame.
The bulb-clips must have the wire pig-tails both pointing IN, thus the wires "cross" on top of the plastic light housing.
Good Luck Chasing the Orange Wire #40 Circuit.
Clock
Dome Light
Foot Well RH / LH Lights
Spare Tire Light
Courtesy Light "Timer" Box
Anti Theft Relay
Anti Theft Horn
Power Antenna
Cigarette Lighter
Key Buzzer
Power Door Locks
Hopefully I did not miss anything on Your 1979 Model Orange wire circuit.
If I did miss something - I bet the Forum Members will "chime-In"



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