The following 9 service centers are located in Illinois ...

 MAP IT!
Central Service & Repair
1760 W Cortland Ct
Addison, IL    60101
PHONE: +1 630-268-1010
tic1760@aol.com
Map to Central Service & Repair
 
Intermodel Maintenance Group
4358 W. 35th Place
Chicago, IL    60632
PHONE: +1 773-247-7250
Map to Intermodel Maintenance Group
 
Tredroc Tire
2450 Lunt Ave
Elk Grove Village, IL    60007
PHONE: +1 847-956-3600
mlavelle@tredroc.com
Map to Tredroc Tire
 
Tredroc Tire
2450 Lunt Ave
Elk Grove Village, IL    60007
PHONE: +1 (224) 265-4070
Map to Tredroc Tire
 
Heavy Equipment Services Inc
2290 Route 20 East
FREEPORT, IL    61032
PHONE: +1 815-235-7131
Map to Heavy Equipment Services Inc
 
Central Illinios Truck
22570 WEST highway 60
Grayslake, IL    60030
PHONE: +1 847-223-6666
gservice@nimack.com
Map to Central Illinios Truck
 
Chucks Truck Repair
4711 S Lawndale Ave
LYONS, IL    60534
PHONE: +1 708-387-7400
chucks.repair@sbcglobal.net
Map to Chucks Truck Repair
 
Schumacher's Tire Service
2015 County Rd 1150 North
Roanoke, IL    61561
PHONE: +1 309-744-2497
schumacherstyre@yahoo.com
Map to Schumacher's Tire Service
 
Central Illinois Truck
4301 N Bell School Rd
Rockford, IL    61111
PHONE: +1 815-639-2000
jgarner@cittrucks.com
Map to Central Illinois Truck
 

We also have at least one Protrak service center in the following other states/provinces:

Alberta
Alabama
Arizona
California
Colorado
Florida
Georgia
Iowa
Idaho
Indiana
Kansas
Kentucky
Massachusetts
Michigan
Minnesota
Missouri
Mississippi
Montana
North Carolina
North Dakota
Nebraska
New Jersey
New Mexico
Nevada
New York
Ohio
Oklahoma
Ontario
Oregon
Pennsylvania
Quebec
South Dakota
Saskatchewan
Texas
Utah
Virginia
Washington
Wisconsin
West Virginia
Wyoming