Replacing the Ignition Switch in Your 1971-1975 Mercury Monterey
Everything you need to know about diagnosing and replacing the ignition switch on your classic Monterey.
- Failure symptoms often mimic a bad battery or starter, such as a no-start condition or stalling.
- The ignition switch is a separate electrical part from the keyed lock cylinder on these models.
- Standard Ignition is a reputable aftermarket brand for this component.
- Verify the part's connector against your old one before buying, as different switches were used in this year range.
Is Your Monterey's Ignition Switch Failing?
A bad ignition switch in a classic car like the Mercury Monterey can cause confusing problems that might seem like a dead battery or a bad starter. Because the switch controls power to so many components, its failure can show up in different ways. Over decades of use, the internal electrical contacts wear out, leading to a poor connection.
Common Symptoms of Failure:
- Car Won't Start: You turn the key and nothing happens—no click, no crank. Power isn't reaching the starter motor.
- Starts and Immediately Stalls: The switch may provide enough power to start the engine but then fail, cutting power to the ignition or fuel system.
- Flickering Dashboard Lights: As you turn the key or drive, the dashboard lights may flicker or cut out entirely, indicating a loose internal connection in the switch.
- Key Is Hard to Turn or Stuck: While this can also be the key or lock cylinder, a worn or binding ignition switch can make it difficult to turn the key through its positions.
- Accessories Don't Work: The 'Accessory' position on your ignition may fail to power the radio or other systems.
Stalling While Driving
A severely worn ignition switch can cut power while you are driving, causing the engine to shut off. This is a serious safety risk, as you will lose power steering and power brakes. If your Monterey is stalling unexpectedly, investigate the ignition system immediately.
Choosing the Right Aftermarket Ignition Switch
For a vehicle like the 1971-1975 Monterey, finding a brand-new Original Equipment (OEM) part from Ford is nearly impossible. The market consists of New Old Stock (NOS) parts, which are rare and expensive, and new aftermarket parts.
Brand Spotlight: Standard Ignition (Standard Motor Products)
Standard Motor Products (SMP) is a common and trusted brand for classic car electrical parts. Their ignition switches are designed to be direct replacements for the original. They use copper alloy conductors to ensure good electrical conductivity and test their switches to verify mechanical and electrical performance. For a simple, non-electronic part like this, a quality aftermarket switch from a reputable brand like Standard Ignition is a reliable and cost-effective choice.
Check Your Year Carefully
Ford used different ignition switches during this period. Part listings show that 1971-1972 models often use a different switch than 1973-1974 models. Always verify the part number and connector shape against your original switch before ordering to ensure you get the correct one for your specific year.
Replacement Cost
Replacing the ignition switch is a manageable job for a DIY mechanic with basic tools. The part itself is affordable, and labor costs at a shop are typically low due to the straightforward nature of the repair on older vehicles.
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Ignition Switch | $57.12 |
| Shop Labor | $100 - $200 |
| Total Estimated Cost | $157 - $257 |
Frequently Asked Questions
Do I need to replace the key and lock cylinder too?
Not necessarily. The ignition switch and the ignition lock cylinder (where you insert the key) are separate parts on your Monterey. If your only problems are electrical (no start, stalling, flickering lights), you likely only need the switch. If your key is physically stuck or won't turn, the problem might be the lock cylinder instead.
Are there any recalls for the ignition switch on my Monterey?
No, there are no active recalls from the NHTSA for the ignition switch on 1971-1975 Mercury Monterey models. Major ignition switch recalls by Ford and GM in the past involved different models and different decades.
How difficult is it to replace the ignition switch myself?
For a classic car, this is usually a fairly simple job. It involves removing the lower steering column covers to access the switch, disconnecting the wiring harness, unbolting the old switch, and installing the new one. You will need basic hand tools. The difficulty is low for someone with some mechanical experience.
What is the difference between an ignition switch and a starter solenoid?
The ignition switch is the low-current switch you operate with your key. It sends a signal to the starter solenoid. The starter solenoid (or relay) is a heavy-duty switch that handles the high electrical current needed to turn the starter motor. A "click" with no crank often points to a bad starter or solenoid, while complete silence often points to a bad ignition switch or battery.
Technical Specifications
OEM Part Numbers: D1AZ-11572-C D1AZ-11572-A D4DZ-11572-A D3AZ-11572-A
Mounting Location: Steering Column. Terminal Quantity: 7 to 11 depending on year/application.
We Have This Part in Stock
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.