P1308
A/C Clutch Circuit Fault.
- Lincoln
- Powertrain
- Manufacturer code
- Low severity
How this code is built
- P
- SystemPowertrain
- 1
- Defined byThe manufacturer
- 3
- AreaIgnition system or misfire
- 08
- FaultThe specific fault in that area
What it means
On a Lincoln, P1308 means the powertrain control module has detected a fault in the air conditioning compressor clutch circuit. It sets when the voltage or current it sees on the clutch control circuit does not match what it commanded, for example an open circuit, a short to ground or a short to power. The exact circuit layout and test values depend on the model and year.
Symptoms
- Air conditioning blows warm or does not cool
- Compressor clutch does not engage when A/C is switched on
- Compressor clutch engages erratically or cycles rapidly
- Malfunction indicator lamp on
- A/C button works but there is no change in cabin temperature
Possible causes
- Open or shorted compressor clutch coillikely
- Damaged wiring, chafed loom or corroded connector at the compressor or relaylikely
- Faulty A/C clutch relay or its socketlikely
- Blown fuse in the clutch feed or control circuitpossible
- Incorrect or excessive clutch air gap causing poor engagementpossible
- Fault in the powertrain control module driver circuitrare
How to diagnose
- Read all stored codes and freeze frame data, and note whether A/C was requested when the fault set
- Check the relevant A/C fuses and visually inspect the relay and its socket for heat damage or corrosion
- Inspect the wiring and connector at the compressor clutch for chafing, water ingress and poor terminal tension
- With A/C on, check that the clutch relay clicks and that voltage reaches the clutch connector
- Measure the clutch coil resistance and compare it with the specification for that model and compressor
- Check the clutch circuit for continuity and for shorts to ground or power, following the wiring diagram for that vehicle
- Inspect the clutch air gap and the condition of the clutch plate, and check the refrigerant pressure is within range as low pressure can inhibit the clutch
- Swap in a known good relay or command the clutch on with a scan tool to test the control side before suspecting the control module
How to fix
- Replace the compressor clutch coil or clutch assembly if the coil is open, shorted or out of specification
- Repair damaged wiring and clean or replace corroded connectors and terminals
- Replace the faulty A/C clutch relay, and the fuse if it has blown after finding why it failed
- Adjust or replace the clutch plate and set the correct air gap
- Repair or replace the powertrain control module only after all wiring and component faults are ruled out
Can I keep driving?
Low severity
The car is safe to drive, as this fault only affects the air conditioning. Book it in soon, particularly if you need demisting, as the A/C often helps clear the windscreen.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.