That wire on the Rottendog board probably connected to the +5 volt wire at pin 5 on the connector of the pop bumper driver board also located on the lower playfield.

The connector pinout on pop bumper driver boards is:

1: Solenoid voltage input (about 30 volts DC)
2: Output to coil
3: KEY
4: Switch input
5: +5v power input to operate board
6: Logic ground

Be sure your wires are connected correctly or you'll damage the board. In your picture, it looks like you have the connected plugged in WRONG! The connector pin numbers 1 and 6 are silkscreened on the Rottendog board but not on original genuine Gottlieb pop bumper driver boards.

Ok here is the deal, Haunted House from the factory did not use a PBDB (Pop Bumper Driver Board) on the VUK. They used a drive transistor, but the design was flawed and folks got tired of replacing burnt transistors/coils and developed an aftermarket field retrofit to add the PBDB to the VUK..

Here is the rework instructions and that should help you figure it out..

http://arcadecontrols.com/files/Manuals/Black%20Hole%20-%20Haunted%20House%20Repair%20Guide.pdf

Refer to page 37 and 38...

Step one, look at your picture, see how you have two black wires on on end?

Where do those go? If they go to the coil then by the logic diagram I provided, they are pins 1 and 2.

Now look at how the connector is plugged into the PBDB, note how there is a 1 and a 6 etched on the board?

IF (assuming the two black wires went to the coil) the two black wires go to the coil, AND you have them orientated like in the picture, you have the connector plugged in 180 degrees out and may have destroyed that PBDB...

If Ken and I are correct, you need to rotate that connector so that the 2 black wires that are on one end, are toward the 1 side as etched on the PBDB.

Once you have that done, then the remaining wires, 4 5 and 6 are as follows;
#4 the one with the stripe should go off to the K relay right next to the PBDB.
#5 the red one, should be spliced into any #5 wire on the nearest other PBDB.
#6 the black one, should be tied to ground somewhere. And also plugged in near the 6 etched on the PBDB...

One you do that, if it still does not work, you can rotate that PBDB into any other position such as the 5 target bank reset to see if it is fried.