Need a Switched Ground

im wiring something up and i need a switched ground wire to tap into. (ie grounded when ignition is OFF, open ground with ignition OFF)

preferably near the AC controls.

98XJ 4.0

Last time I looked, no such aminal. Why do you need one - can't you work with switched power?

The easiest way to make one would be to wire a relay to ground, trigger it with the key ON signal, and use that. Still - it's usually easier to find switched power, so I ask again - what are you working on? With understanding comes knowledge...

5-90

flashing "alarm" LED

i had one that was working when a switched power was given juice but that crapped out and i bought a new LED. this one is activated with a switched ground

Figures. No sense in making anything simple, is there?

The relay will still be your best bet. The regular Bosch/Hella relays (with terminals 87 and 87a) can be used to either turn a circuit ON or OFF when power is applied, so use those as you will.

It's worth noting that these are the same relays in use in most XJ's for OEM wiring - take a check. If your relays are about 1" cube (not including terminals) and are labelled something like "30, 85, 86, 87, 87a" they're the standard units. These can be had from Parts Express (www.partsexpress.com) for about $3 each - I buy them by the dozen for use in other projects as well. Can't do any harm to have spares while you're about it. They should also have prewired "relay sockets" you can use to make connections and replacement easier (I source relay blocks from another vendor, because I like them better.)

5-90

<scratching head>
What is the usual application of this light? Trying to think of where you'd normally have a switched ground..

gjxj said:

<scratching head>
What is the usual application of this light? Trying to think of where you'd normally have a switched ground..

Click to expand...

X2 That's what I was thinking,it sounded odd but he seemed sure so I didn't question it. :wierd:

Interesting. This made me think of those old positive ground electrical systems.

LouisianaZJ, how about reversing the polarity of the LED electronics?

Just use the relay, and wire it so when the ignition is on the circuit is open.