Relay temporarily loosing ground, use cap

The solenoid is set up to power two HID ballasts. It's receiving it's signal from the ground switched H4 headlight. I have a diode wired between the high and low ground going to the solenoid. When I switch from low to hi my ballasts stay on, however, when I go back to low my ballasts turn off momentarily during the switch, which causes my lights to flash (obviously not good). Any idea what's going on here? I was going to add a capacitor to the + line to try and stop the momentary disconnect. EDIT: I added a 25v 470 mf capacitor with the + and - across the 85 and 86 pin. After running for about a minute the capacitor popped and started smoking. Thanks, Milan Vehicle: Toyota 4Runner with H4 lights ground switched.

So it popped because I wired it backwards, not because there was too much current? Thx for the help, Milan