Section 01-17: Convertible
1994 Mustang Workshop Manual
DIAGNOSIS AND TESTING

Pinpoint Tests

  

PINPOINT TEST A: CONVERTIBLE TOP DOES NOT RAISE AND/OR LOWER

 

A1 CHECK CIRCUIT 298

Yes
GO to A3.

No
GO to A2.

 

A2 CHECK CIRCUIT 298 SUPPLY

Yes
SERVICE Circuit 298 (P/O) for open. RESTORE vehicle. RETEST system.

No
SERVICE Circuit 298 (P/O) for short. REPLACE Fuse 1 (15A). RESTORE vehicle. RETEST system.

 

A3 CHECK TOP SWITCH

  • Reconnect connector to top switch.
  • Turn ignition switch to RUN position.
  • Use a 12-volt test lamp to back probe Circuits 588 (P) and 688 (GY/LB).
  • Toggle switch to raise position to check Circuit 588 (P) and to lower position to check Circuit 688 (GY/LB).
  • Does test lamp light?
Yes
GO to A4.

No
REPLACE convertible top switch. RESTORE vehicle. RETEST system.

 

A4 CHECK CIRCUIT 588 (P)

  • Disconnect connector from raise relay .
  • Turn ignition switch to RUN position.
  • Connect a 12-volt test lamp between Pin 5, Circuit 588 (P) and a good ground.
  • Toggle switch to the raise position.
  • Does test lamp light?
Yes
GO to A5.

No
SERVICE Circuit 588 (P) for open. RESTORE vehicle. RETEST system.

 

A5 CHECK CIRCUIT 688 (GY/LB)

  • Disconnect connector from lower relay .
  • Turn ignition switch to RUN position.
  • Connect a 12-volt test lamp between Pin 5, Circuit 688 (GY/LB) and a good ground.
  • Toggle switch to the lower position.
  • Does test lamp light?
Yes
GO to A6.

No
SERVICE Circuit 688 (GY/LB) for open circuit. RESTORE vehicle. RETEST system.

 

A6 CHECK CIRCUIT 170 (R/LB)

  • Ignition switch in OFF position.
  • Connect a 12-volt test lamp between Circuit 170 (R/LB) and a good ground at Pin 3 of both relay connectors.
  • Does test lamp light?
Yes
GO to A7.

No
GO to A8.

 

A7 CHECK RELAYS GROUND

  • Ignition switch in OFF position.
  • Connect a self-powered test lamp between Pin 2, Circuit 57 (BK) and a good ground of each relay connector.
  • Does test lamp light?
Yes
GO to A9.

No
SERVICE Circuit 57 (BK) for open. RESTORE vehicle. RETEST system.

 

A8 CHECK SUPPLY TO CIRCUIT 170 (R/LB)

  • Gain access to convertible top circuit breaker (30A) at power distribution box and harness . Remove circuit breaker.
  • Using an ohmmeter connected to a known good ground, connect second lead to output side of convertible top circuit breaker (30A). Measure resistance.
  • Is resistance 5 ohms or less?
Yes
SERVICE Circuit 170 (R/LB) for short. RESTORE vehicle. RETEST system.

No
SERVICE Circuit 170 (R/LB) for open. RESTORE vehicle. RETEST system.

 

A9 CHECK RAISE RELAY OPERATION

  • Reconnect connector to raise relay .
  • Turn ignition switch to RUN position.
  • Use a 12-volt test lamp to back-probe Pin 1, Circuit 903 (R).
  • Toggle top switch to the raise position.
  • Does test lamp light?
Yes
GO to A10.

No
REPLACE raise relay . RESTORE vehicle. RETEST system.

 

A10 CHECK LOWER RELAY OPERATION

  • Reconnect connector to lower relay .
  • Turn ignition switch to RUN position.
  • Use a 12-volt test lamp to back-probe Pin 1, Circuit 902 (Y).
  • Toggle top switch to the lower position.
  • Does test lamp light?
Yes
GO to A11.

No
REPLACE lower relay . RESTORE vehicle. RETEST system.

 

A11 CHECK CIRCUIT 903 (R)

  • Disconnect folding top hydraulic lift motor connector.
  • Turn ignition switch to RUN position.
  • Connect a 12-volt test lamp between Circuit 902 (Y) and a good ground.
  • Toggle top switch to raise and lower.
  • Does test lamp light?
Yes
GO to A12.

No
SERVICE Circuit 903 (R) for open. RESTORE vehicle. RETEST system.

 

A12 CHECK CIRCUIT 902 (Y)

  • Disconnect folding top hydraulic lift motor connector.
  • Turn ignition switch to RUN position.
  • Connect a 12-volt test lamp between Circuit 902 (Y) and a good ground.
  • Toggle top switch to raise and lower.
  • Does test lamp light?
Yes
REPLACE folding top hydraulic lift motor and plate kit . RESTORE vehicle. RETEST system.

No
SERVICE Circuit 902 (Y) for open. RESTORE vehicle. RETEST system.

  

PINPOINT TEST B: TOP HESITATES AND/OR COMES UP UNEVEN

 

B1 CHECK TOP UP/DOWN OPERATION

  • Actuate folding top switch in both up and down position.
  • Observe folding top operation as folding top is lowered or raised.
  • Did folding top operate to full up or full down position without hesitation?
Yes
GO to B3.

No
GO to B2.

 

B2 CHECK FOLDING TOP HYDRAULIC LIFT MOTOR OPERATION

  • Listen to folding top hydraulic lift motor and plate kit as top is lowered or raised.
  • Did folding top hydraulic lift motor and plate kit stop and then continue?
Yes
GO to Pinpoint Test A.

No
GO to B3.

 

B3 CHECK TOP LINKAGE

  • Observe top linkage at both sides of vehicle as top is lowered or raised.
  • Did linkage operate smoothly without binding?
Yes
GO to Pinpoint Test D.

No
ADJUST top linkage as outlined. SERVICE as necessary.

  

PINPOINT TEST C: TOP DOES NOT RAISE OR DOES NOT GO ALL THE WAY UP

 

C1 CHECK TOP OPERATION

  • Turn ignition switch to the RUN position.
  • Actuate folding top switch to the up position.
  • Listen for folding top hydraulic lift motor and plate kit operation.
  • Does folding top hydraulic lift motor and plate kit run?
Yes
GO to C2.

No
GO to Pinpoint Test A.

 

C2 CHECK TOP LINKAGE

  • Actuating folding top in the up position observe folding top linkage on both sides of vehicle.
  • Did folding top linkage attempt to raise folding top?
Yes
SERVICE as necessary.

No
GO to Pinpoint Test D.

  

PINPOINT TEST D: HYDRAULIC SYSTEM

 

D1 CHECK RESERVOIR FLUID LEVEL

  • Gain access to folding top hydraulic lift motor and plate kit as outlined.
  • Place absorbent cloth below the reservoir filler plug.
  • Remove the filler plug and check fluid level.

    NOTE: Fluid should be level with the bottom of the filler plug hole.

  • Is fluid level OK?
Yes
GO to D4.

No
GO to D2.

 

D2 CHECK SYSTEM FOR LEAKS

  • Visually inspect all folding top motor upper and lower hose for damage.
  • Check all fittings at folding top hydraulic lift motor and plate kit and folding top hydraulic cylinders.
  • Are any leaks visible?
Yes
SERVICE as necessary. GO to D3.

No
GO to D3.

 

D3 BLEED HYDRAULIC SYSTEM

  • Fill reservoir with Synthetic Mercon® Multi-Purpose Automatic Transmission fluid E6AZ-19582-B (ESR-M2C163-AZ) or equivalent. Fill reservoir to bottom of filler plug hole. Install filler plug.
  • Start engine.
  • Cycle the folding top several times to purge air out of the system.

    NOTE: Refill reservoir as necessary during the bleeding operation.

  • Is bleeding operation OK?
Yes
GO to D4.

No
If folding top hydraulic lift motor and plate kit did not operate, GO to Pinpoint Test A. If folding top hydraulic lift motor and plate kit did operate, PERFORM Test Step D2 again, and SERVICE as necessary.

 

D4 CHECK FOLDING TOP HYDRAULIC CYLINDERS

  • While cycling top, observe folding top hydraulic cylinder operation.
  • Is folding top hydraulic cylinder operation OK?
Yes
GO to D5.

No
REPLACE damaged folding top hydraulic cylinder .

 CAUTION: The reservoir must be vented in order to equalize the pressure. This minimizes the possibility of fluid spraying on the trim and paint when the folding top motor upper and lower hoses are disconnected.

 

D5 CHECK FOLDING TOP MOTOR UPPER AND LOWER HOSES

  • While cycling top, observe folding top motor upper and lower hose for kinks or misrouting.
  • Are folding top motor upper and lower hoses OK?
Yes
If folding top is not operational, GO to Pinpoint Test A. RESTORE vehicle. RETEST system.

No
REPLACE damaged folding top motor upper and lower hose .

 CAUTION: The reservoir must be vented in order to equalize the pressure. This minimizes the possibility of fluid spraying on the trim and paint when the hose(s) is disconnected.