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I replaced the entire wiring harness on my 1970 Nova 350 and…

I replaced the entire...

I replaced the entire wiring harness on my 1970 Nova 350 and it ran great but it recently just died no power at all. I replaced the horn relay and have headlights but when I turn the ignition switch it blows the in line fuse to the horn relay. I have been reviewing all the wiring and can't see to find the short.

Mechanic's Assistant: Is the power loss consistent, or does it fluctuate?

The car was fine at first but then one day the entire electrical system shut off completely dead. The hot wire to the horn relay fried and I replaced the relay and ran an in line fuse for protection. You can turn on the headlights with no problem but as soon as you turn the key the fuse pops and the entire system is dead again.

Mechanic's Assistant: Are you fixing your Nova yourself? What have you tried so far?

Yes I am fixing myself with limited electrical knowledge. I went under the dash to make sure there was no fried wires and traced all wires back from the new wiring harness to the bloack and under dash.

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

I am completely stumped

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Answered in 2 hours by:
1/16/2018
Don - Mo Lurch
Don - Mo Lurch, Classic Car Mechanic
Category: Classic Car
Satisfied Customers: 21,470
Experience: Heavy Line Mech-, Mobile Electronics. Sales, Installation & Repair for 30 years. R/S, etc.
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sorry for the delay............
What AMP is the Fuse?
Have you tested Voltage on the main wire that you put the In Line Fuse on?
Is the Starter shorted?

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Customer reply replied 7 months ago
10amp
How do you test the main wire?
The starter is not shorted but when you turn the key on it blows the in line 10amp fuse connected to the horn relay which knocks out the entire system
Customer reply replied 7 months ago
The car ran great at first and I was driving with not a problem then one day I drove 2 blocks and the engine just stopped dead and smoke came out from under the hood and I found the hot wire to the horn relay burnt. So I replaced the horn relay and put in the fuse system to protect.

What size wire is this, that the Fuse is in?

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Customer reply replied 7 months ago
16

IF this is the main feed wire that comes from the Starter Solenoid, to the Coil +, to the Wipers, then to the Horn Relay, a "10 amp" Fuse is not large enough as that wire feeds to many components
I believe the original wire should be minimum 14 gauge & will be at least "20 amps"

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The reason I asked about the starter, is the Starter Solenoid draws high AMPs when cranking and usually requires at least 20 amp fuse also

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Customer reply replied 7 months ago
Ok I understand and will change the fuse to 20amp
The problem is as soon as the key is turned to "accessory" or "on" the fuse pops so the starter is not even given a change to crank
Customer reply replied 7 months ago
sorry should have read a chance to crank
Customer reply replied 7 months ago
The starter and the engine harness wiring is all new
Customer reply replied 7 months ago
When the engine first stopped on me a little bit of smoke came out from under the middle area of the dash very minor amount of smoke. And as I turned the key to start the car that is when a lot of smoke came out from under the hood at the horn relay area and that is when I noticed the wire connected to the horn relay was burnt.

THANK YOU for the added info.......
You need to first check the Ignition Switch connections
Then test each wire on the Ignition Switch for Voltage + in each position (Accessory, ON & Start)
Then the + Coil wire with Key ON...engine OFF
check Voltage + on the Horn Relay
IF you need further, let me know

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Customer reply replied 7 months ago
Ok I think maybe I need to have the car towed to an electrical shop for this as I am not sure how to accomplish the process.

I understand, as Electrical can be tedious & you need to be sure the proper AMP wire & Fuse is used to prevent shorts, overheating of wires & fire
Just be sure you have a person that knows this years wiring, as that would cut the time considerably..........
Smoke is not a good thing & should be checked carefully for any burned componentsLet me know if you need further

.

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Don - Mo Lurch
Don - Mo Lurch, Classic Car Mechanic
Category: Classic Car
Satisfied Customers: 21,470
Experience: Heavy Line Mech-, Mobile Electronics. Sales, Installation & Repair for 30 years. R/S, etc.
Verified
Don - Mo Lurch and 87 other Classic Car Specialists are ready to help you
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Customer reply replied 7 months ago
Thank you for your time it was greatly appreciated!!

THANK YOU
Thanks for using J/A

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