Hi,
My Mk1 air bag light has been flashing for a while.
5 flashes, then one flash. There is then a long pause then it repeats.
Every so often it totally stops.
Has anyone experienced this before? Is there anything obvious that I can check?
Very new to electronics so anything helps. Thanks 
Translating Engine Fault Codes
Use the information below to look up the meaning of any outputted fault codes from your engine. Codes will be output once the LED indicator light extinguishes for the first time, and then shown as a series of long and short flashes. Count the number of long flashes, these are the tens, then count the short flashes, the units. Four long flashes followed by three short flashes would indicate fault code 43. Multiple codes are output one at a time, separated by a pause.
MX5 Engine DTC Fault Codes;
1 – Ignition pulse
2 – Ne signal
3 – G signal
4 – SGT signal (1.8L)
8 – Airflow meter
9 – Water thermistor
10 - Intake air thermistor in airflow meter
12 - Throttle position sensor
14 -Atmospheric pressure sensor
15 - Oxygen sensor (output too low)
16 - EGR function sensor (1.8L)
17 - Oxygen sensor (output not changing)
25 - PRC solenoid valve (1.8L)
26 - Solenoid valve (Evaporative canister purge)
27 - EGR solenoid valve (vacuum)(1.8L)
28 - EGR solenoid valve (vent)(1.8L)
34 - Idle air control (1.8L)
36 - Idle speed control valve
Clearing Engine Fault Codes
Most (but not all) fault codes will remain in memory until they are cleared. It is a good idea to clear all codes before starting to diagnose faults, to ensure all codes are current.
To clear all your engine fault codes, remove the jumper cable from the diagnostic connector, disconnect the battery Negative (-) cable, then press the brake, and sound the horn to remove any excess power from the system. Reconnect the battery again after about 20 seconds. You may then need to start and drive the car a short distance to refresh any faults that may be discovered by the On-Board Diagnostic system.
Sounds like code 51 which is an internal failure of the air bag control unit, replacement is usually the only fix. There is a list of air bag fault codes in the downloads area of the main club site.