1. Identify the Problem: Which Fan(s) Aren't Working?
Your 1990 Trans Am likely has two electric cooling fans: a low-speed fan and a high-speed fan. Do *neither* work, or is just one malfunctioning? This will help narrow down the possibilities.
2. Check the Fuses & Relays:
* Locate the fuse box: Find your car's under-hood fuse box and interior fuse panel (usually under the dash). Consult your owner's manual for the exact locations and fuse ratings for the cooling fans.
* Inspect the fuses: Carefully check the fuses visually for a blown filament (a break in the wire). Replace any blown fuses with fuses of the *same rating*. Don't use a higher amperage fuse as this is a fire hazard.
* Locate and check the relays: The cooling fan system often uses relays to switch the higher current needed to power the fans. These relays are usually found in the under-hood fuse box. They may be labeled "FAN" or something similar. You can often visually inspect relays by looking for corrosion or other damage, but a more definitive test involves swapping a known good relay with the fan relay to see if that resolves the issue. Auto parts stores can test your relays if you are unsure.
3. Test the Fan Motors Directly:
If the fuses and relays are good, the problem is likely with the fan motor(s) themselves or the wiring to them.
* Direct power test (Caution!): This step requires some electrical knowledge and caution. Disconnect the battery negative terminal before proceeding. You'll need jumper wires and a suitable power source (like a battery). Carefully connect the positive wire to the positive terminal of the fan motor and the negative wire to the negative terminal. If the fan spins, the motor is good and the problem is with the wiring or control circuit. If it doesn't spin, the motor is faulty and needs replacing. Be extremely careful not to short circuit anything.
4. Wiring and Connections:
* Inspect the wiring harness: Carefully check the wiring harness leading to the fans for any broken wires, chafing, or corrosion. Pay close attention to the connectors.
* Clean connectors: If you find corrosion on the connectors, clean them with electrical contact cleaner.
5. Cooling Fan Control Module (CFM) or PCM (Powertrain Control Module):
The fans are controlled by either a dedicated CFM or the PCM. A faulty CFM or a problem with the PCM's fan control function is less likely but possible. Diagnosing these requires more advanced tools and knowledge. A scan tool capable of reading your car's computer codes might help identify if the PCM is throwing any relevant trouble codes.
6. Temperature Sensor:
The car's coolant temperature sensor signals the PCM or CFM when to turn on the fans. A faulty sensor could prevent the fans from ever turning on. This would usually result in the fans not working at all, even when the engine is significantly overheated.
Where to Find Parts:
You can find replacement cooling fan motors, relays, and fuses at auto parts stores (like AutoZone, Advance Auto Parts, NAPA) or online retailers. Be sure to specify your 1990 Pontiac Trans Am GTA when ordering parts.
Important Considerations:
* Overheating Damage: If your car is overheating, *do not continue to drive it*. Overheating can cause catastrophic engine damage.
* Professional Help: If you're not comfortable working with car electrical systems, it's best to take your car to a qualified mechanic. Improperly diagnosing and repairing electrical issues can lead to further problems.
* Owner's Manual: Refer to your owner's manual for diagrams and specific information about your car's cooling system.
By systematically checking these components, you'll significantly improve your chances of identifying the source of the problem and getting your cooling fans working again. Remember safety first, and don't hesitate to seek professional help if needed.
