Wiring thought I was done

[Davidsw 4]

The car has been fully restored and I thought tested . Oh well 

 

ok fuse 2 , 30 amp blew on way to mot . It made it through but I noticed the brake light stopped working on the way back . I replaced fuse 2 , 3 times . I noticed the wires going to the brake pedal had got hot . But the cause unknown . Well after taking dash out pulling fuse box apart and back lights I noticed the the earth to the rear light cluster had also got hot but it looked like it had done this over a period of time . This is the earth wire in the earth block on the inside behind the light . I pulled this earth off and the brake lights started working after I replaced the wires to the pedal . I’ve had the car on test and no failure but I can see with a voltmeter that the earth wire has 12v on it when I press the brake pedal . If I leave the earth wire disconnected all is good . 

 

I would like to find the cause of this . 

 

Any ideas 

 

 

thanks 

[jackherer 543]

I'm not sure what your fault is but I think fuse 2 should be a 25A not a 30A which might explain why your wiring has melted before the fuse has blown.

 

 

[Davidsw 4]

Ok thanks for that I’ll down grade . Funney thing is I ordered a replacement look from Peugeot spares off eBay . That loom is also burnt on the same earth . 

[toolie72 67 1 Cars]

Not sure I’m following what you mean

But 12 volt going to earth is just the circuit closing ie when the switch has made contact which in a dc circuit is correct ,+ goes to light goes to -,if it didn’t go to negative then light wouldn’t come on

or is that not what you’re saying?

[Andy 105 1 Cars]

Hmm. 12v actually at the earth wire is a problem. The 12v should be dropped across the device being activated, (buib etc) . The earth is there to complete  the path back to the battery and should be at virtually zero potential . If not, then the live feed must be bypassing the device being operated, hence the high current in the wire and consequent fuse blowing/ wire overheating ( although the latter  should not happen if the former is the correct rating ) as Jackherer said

[Tom Fenton 1,524]

Sounds to me like you have plugged the flying 12v that exists at the rear of the car into the earth block.  A photo would help but the wire is not used on most 205's

[Andy 105 1 Cars]

Agreed. You have grounded at 12v supply. Hence the melting !

[Davidsw 4]

Hi 

 

yes I believe I grounded the feed for the towing hook during the restoration . I’ve since replaced the fuse box just because I wanted to get to know how it all hangs . I’ve tested the car now for half an hour with the brake lights on and everything else . Every thing works now 

 

ive rapped the damage in heat shrink and replace the two wires going to the brake pedal . 

 

Thanks People 

 

ive actually got a spare wiring loom from the engine back it’s very good for reverse engineering . 

 

 

Edited November 20, 2017 by Davidsw

[johnyma22 3]

Thanks for this thread, it pointed me in the right direction to solve my problem :)