I just installed a brake controller in a 2007 chevy suburban and when i touch the brakes the trailer brakes lock up

First you need to have EBCM - electronic brake control module check for DTC'S - diagnostic trouble code's . If the light is on there is a code stored . I think most part stores can do this and for free . After you find out what code is stored , looking up that code in service repair information for diagnostic trouble shooting chart would be next step . There are a few codes too.
DTC C0035 or C0040
DTC C0045 or C0050
DTC C0110
DTC C0131
DTC C0161
DTC C0186
DTC C0196
DTC C0201
DTC C0240
DTC C0241 or P0856
DTC C0244 or P1689
DTC C0245
DTC C0283
DTC C0287
DTC C0290 or C0292
DTC C0455
DTC C0550
DTC C0558

Find the code do the diagnostic's , fix the problem , wiring issue's , a sensor , bad module ,what ever it is . The light will go out then . Here is a sample of code discription .
• DTC C0035 Left Front Wheel Speed Sensor Circuit
• DTC C0040 Right Front Wheel Speed Sensor Circuit

If you're only blowing the fuse while the trailer is plugged in, the problem is in the trailer/wiring. This takes into account that the truck has a factory installed 7 way receptacle. If that's not the case, the problem can be in the incorrectly wired truck and the trailer is ok.

On the truck, looking into the 7 way receptacle should be as follows.
Top left=Tail Lights
Top right=12v steady source/charge line
Left middle=Left turn/brake
Right middle=Right turn/brake
Left bottom=ground
Right bottom=brake controller output
Center=reverse lights if your trailer is equipped.

Your trailer plug should mirror this.

This is the standard.

Check your Brake Switch on the Back of your Brake Pedal, you have loose wires or your switch is not working properly

check fuses also is it manufacture installed or after market installed. if manufacture installed check connections behind the connector. if after market installed check where they spliced wires into the tail light wires behind bumper and any where else that wires could be connected do you have tail lights and brake lights on the suburban send email to [email protected]

Yes

a brake controller has 4 wires on it, Black, white, blue,red.

Black is positive battery 12 volts connect to 30 amp circuit breaker to the battery

White goes to good solid ground

red connects to white wire from the brake switch

blue wire connects to 7 way trailer connector at rear of truck. If the truck has trailer package you will find the blue wire and red wires under brake booster taped to the harness you can connect your blue brake control wire to that blue wire. At the rear of the truck the other end of the blue wire will be taped to a harness under the rear of the truck. you will have to now connect the blue wire to the blue input on your 7 way connector

what type controller did you install? Is this a camper or trailer? Is the controller hydraulic plumbed into master cylyder? Important to know how to adjust rheostat for sensitivity. If set at minimum the system is basically on the edge of not sending any signal to towed unit. The intructions should explain how to make this adjustment. If set too sensitive trailer brakes will lock up before the tow vehcle starts to brake. Controller should be set so trailer starts braking just befor the tow vehcle. If not the trailer will tax the tow vehicle brakes by pushing. Its set right when you feel the combination stretching out. trailer first then tow vehcle. Good luck and remember, if truck brakes first and too hard you risk a jacknife. All light voltages should be system voltage. Brake voltage is variable depending on setting on controller. Understand your breakaway brakes and how they work. breakaway breaks require an auxillary battery. Again, good luck and you know where to find me if I can be of anymore help.

the fifth wire is most likely an auxiliary power wire, for if you wanted lights inside a trailer. (PLEASE RATE MY ANSWER!)

what about the sockets of the lights are they rusted in the contact spot and touching the 2 positive connections