So I'm trying to replace my dome light with LEDs. *I check the LEDs on the battery and a nice bright light. So up at dome wires I check and get 12 V. but when I hook up the LEDs to the dome wires I get a real dim light.

78 Z

Perhaps the ground is bad. The power (+12V) is constant to the dome light. The ground is made when you open the door. Check the switches in the door jambs.

I have I'm stumped. All the switch are working fine.

Polarity? Try turning the bulb around.

I have try that.

test the voltage at the dome light. try wiggling the door switches around see if light gets brighter momentarily. i've had corroded switches

that did that

Might you be checking the LEDS one at a time on the battery and all wired up at the dome light? If so check your wiring-you possibly have series where you should have parallel-or viceversa!

I have check the light in series on the battery and nice and bright. Get 12 v on the dome wires, door switch works fine. I'm stumped

Corrosion in the switch in the dome light or on the contacts?

disconnect battery then measure resistance to ground through the circuit to see where the problem is.

Voltage is potential - not power. If there is a high resistance (compared to a light bulb) in the circui, it might be inconsequential to the very high resistance in your meter. This results in a very small voltage drop as read by your meter. When you insert a bulb, this resistance appears huge and drops a lot of voltage.

Don't measure ohms, measure voltage across the socket contacts with the bulb out and then in. If there is a serious drop in voltage when you insert the bulb, you have high resistance somewhere in the circuit.

As others have said, automotive LEDs usually only work mounted in one direction. First check is to reverse the mounting to see if things get better or worse.

One last thing, I replaced the Malibu lamp bulbs with automotive LEDs. Found the cheap contacts in the lamps and cheap contacts in the Chinese LED didn't always make good contact. You may have the same situation and may have to scuff the contacts with some fine sandpaper to get a good contact.

I'm losing all the power when I plug in the LEDs. Could it be a amp drop because of corrosion?

Exactly, did your bulb work before you tried the LED? First place to look is corrosion in the door switches. These switched supply a ground to the circuit. Try opening each door, snapping the nylon button a couple times and then twisting th button while it is fully extended.