The blower motor on the Pontiac Trans Am blows heat from the vents at different speeds. From time to time, blower motors can develop problems. One such problem is when the blower only works at certain speeds or does not work at certain speeds. One common variation of this problem is when the blower motor does not work at the high setting. There are two troubleshooting approaches to try at home before bringing the car to a mechanic.
Open the hood of the Trans Am and remove the negative battery cable with a socket set.
Locate the relay panel, located behind the battery and pry its cover up and off by hand. On the back side of the relay cover there is a relay diagram. Remove the blower motor relay that corresponds to the diagram by pulling it up and out by hand. Slip a new relay in, replace the negative battery cable and start the Trans Am. Test the heater blower in the "high" position. If it runs, you have solved the problem. If it does not run, move on to other troubleshooting methods.
Pull the replacement relay out and put the original back in. Return the replacement relay to a parts store or store it on the side for later use.
Remove the lower dash board panel, beneath the glove compartment, by pushing in with a flat head screwdriver against the retaining pins. Pull the panel out section by section while pressing against the pins until it is completely removed.
Find the blower motor resistor, which is housed directly behind the blower motor. Disconnect the plastic wiring harness attached to the blower motor resistor by pushing in on the two side tabs and pulling outwards.
Remove the two bolts holding the blower motor resistor in place with the socket set. Slide the old resistor out, put the new one in its place and then put the bolts back in and tighten them with the socket set. Plug the wiring harness into the back of the new blower motor resistor.
Start the Trans Am and place the heater on. Test each setting. If the blower blows on all settings, including high, the problem is solved. If the blower still will not blow at the high setting, then bring the vehicle in to a mechanic.
