Trucks used to have plug in connectors for cases like yours. They would usually be situated under the front bumper, or through the rad. grill.
I am told (I'm a bit out of date!) that they stopped doing this some time ago ('elf an' safety, or more reliable trucks?) so yours may be too modern.
Looks like you will have to crawl underneath and wind them off manually (compressing the actuating spring).
MAKE SURE YOU CHOCK THE WHEELS !
Mr. Toad
August 2008