Mercury Cougar Relay Guide for Electrical Problems (1999-2002)
Fix common electrical issues like a no-start or failing A/C by understanding your Cougar's relays.
- This guide and part are ONLY for the 1999-2002 Cougar, which uses individual plug-in relays.
- A 'crank-no-start' issue is very commonly caused by a failed fuel pump relay.
- Use the 'swap test' by trading the suspect relay with an identical one (like the horn relay) to easily diagnose the problem.
- Replacement is extremely easy: just pull the old relay out and plug the new one in.
A Tale of Two Cougars: Why This Guide is for 1999-2002 Models
It is critical to know that the name "Mercury Cougar" covers two very different cars in this era. The 1995-1997 models are rear-wheel drive and use a single, complex computer called a Constant Control Relay Module (CCRM) that contains multiple relays soldered inside. This guide and the typical, inexpensive aftermarket relays available are NOT for those cars.
This guide is for the 1999-2002 Mercury Cougar, which is a front-wheel-drive sport compact. These models use simple, individual, plug-in relays that are easy to access and replace. These are often identical and interchangeable for different systems.
Symptoms of a Failing Relay
A bad relay usually results in the complete, sudden failure of the component it controls. Symptoms depend entirely on which relay has failed:
- Bad Fuel Pump Relay: This is a very common failure. The most frequent symptom is an engine that cranks normally but will not start. You may also experience the engine stalling suddenly while driving 🎬 See how to troubleshoot fuel pump and relay starting problems. or intermittent starting problems.
- Bad A/C Compressor Relay: The air conditioning will blow warm or room-temperature air. You will not hear the typical 'click' from the engine bay when you turn the A/C on, which is the sound of the compressor clutch engaging.
- Bad Horn Relay: The horn will not work when you press it.
- Bad Cooling Fan Relay: The engine may overheat in traffic as the radiator cooling fan fails to turn on.
Pro Tip: The Relay Swap Test
The easiest way to diagnose a bad relay is to swap it with a known good one. Your Cougar uses several identical relays. For example, if you suspect your A/C relay is bad, you can swap it with the horn relay. If the A/C now works and the horn does not, you have confirmed the relay is faulty. Always check the diagram on the fuse box cover to locate the relays.
Choosing the Right Aftermarket Relay
For a simple part like a relay, there is little difference between OEM and a quality aftermarket replacement. Brands like 'Replacement' offer a cost-effective part that meets original specifications. Since these relays are often sold as multi-purpose, the key is to match the pin configuration (the number and arrangement of the metal prongs) to your old part. The common relay for the 1999-2002 Cougar is a 5-pin, 12-volt unit.
Potential for Misdiagnosis: A Note on a Recall
Some 1999-2000 Cougars with the 2.5L V6 were recalled for a misrouted battery cable (NHTSA Recall 01V031000). This could short circuit, causing a stall or a no-start condition, symptoms that are very similar to a bad fuel pump relay. It's worth checking that your battery cables are secure and not rubbing against other components.
| Part Type | Price Range |
|---|---|
| New Aftermarket | $10 - $20 |
| New OEM (Motorcraft) | $15 - $30 |
| Used OEM | $5 - $15 |
Frequently Asked Questions (FAQ)
Where is the fuel pump relay on my 2000 Mercury Cougar?
The fuel pump relay is located in the power distribution box in the engine compartment, near the battery. The underside of the box cover has a diagram showing the location of each relay.
Can I drive with a bad relay?
It depends. If the A/C or horn relay is bad, the car is safe to drive. If the fuel pump relay is bad, the car will not start or could stall while driving, which is unsafe. If you suspect a fuel pump relay issue, you should not drive the vehicle until it is repaired.
Is replacing a relay a difficult job?
No, this is one of the easiest repairs you can do. It requires no tools. You simply locate the old relay, pull it straight out of its socket, and firmly push the new one in. The entire process takes less than five minutes.
🎬 Watch this quick DIY guide on how to replace a relay.My car cranks but won't start. Is it the relay? 🎬 Watch Billy Bob diagnose a Cougar that cranks but won't start.
A bad fuel pump relay is a very common cause for a crank-no-start condition. Use the swap test described above with another identical relay (like the horn relay) to confirm. If the car starts with the swapped relay, you've found your problem.
Helpful Videos
Technical Specifications
OEM Part Numbers: F57B-14B192-AA FOAZ-14N089-A F6RZ-14N089-AA
5-Pin, 12V DC, SPDT (Single Pole Double Throw) Multi-Purpose Relay
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Mercury Cougar: