Help! Blowing fuses....

[Scooby]

I've got limited time and am stuck. I used the cigarette lighter for a 12V power source run to a switch on the dash used to trigger the relay for some aux lights.

As soon as I turn on the switch I blow the Cig lighter fuse (20A). What does that usually mean? I used the red/yellow for the 12V and the black/yellow for the ground... . (I think it was black/yellow)



Thanks in advance!

 

[jelag]

There are 3 types of failures in wiring... . Opens, shorts and grounds... .

Open - is a broken wire, which means no current, no operation of the device being powered up, with no current flow the fuse won't blow. .

Short - 2 wires touching... on a 120V house circuit this might or might not be a problem based on which phases are touching, on a 12V circuit it usually means something comes on when it's turned off, as the current from the hot circuit shorts across the other wire and powers up the device...

Grounds - this is 120V AC or 12V DC going to ground, thus a connection that exceeds the value of the fuse and it blows...

The center of your lighter is 12+ and the outside is 12- I read your first post about how to get the dash apart to make this connection... and have read this post... I can only assume that you have a connection wrong...

If all your doing is powering a relay from the lighter connection, your draw across the coil of the relay is less than 1/2 amp... I can only assume you have the connections to the relay wrong... do you understand the pin out on the relay and the diagram on the top...

 

[Scooby]

Thanks for your help! It got me thinking that the switch diagram I got off RAdio Shack on line might have been misread (by me!)... ... . and that was the case. It works now!

thanks again Jim!

 

[Scooby]

Jim,

One more question!



The switches have LEDs on them that (I beleive) should only light up when the switch is in the ON position. Instead, the LED on the switch is on all the time - when the ACC is on and/or the truck is running. Otherwise they operate normally. I've never had an issue installing any electrical item on my vehicles so this is rather humbling! Any idea what is going on?



[Background info: I have two switches next to each other that share a 12V power supply and share a ground. One switch runs to the relay to operate the AUX lights and the other switch runs to nothing - it'll operate some backup lights in a few weeks. ]



Thanks!

 

[Prairie Dog]

Try reversing the + connections at the back of the switch to enable the LED only when the switch is "on".

 

[Scooby]

Thanks - that did occur to me... . and I have a feeling that should do it. Of course I have it all put back together!