Ford ranger 2.5 turbo diesel 2004,when engine is running and ticking over,the glow plug sign and the air bag in the control panel flashes alternatley,but does not affect the driving.

I guess instead of waiting for answers here just google it.. or like go for reliable-store.com. u can simply get answers to your questions there..

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If this flashing goes away after a few minutes, this is normal. The glow plugs are on a timer and when the timer works a light should cycle on the dash. Often there may be a clicking noise and the lighting system may flicker when the glow plugs receive power.

Have a load test done on the batter to check for failing cells. For diesels to start any thing less than a fully charged battery good battery is a waste of time as the engine needs fast RPM to heat the air to ignite the fuel and slow rpm's just doesn't cut it.

It is a clear case of the glow plugs malfunction. It had happened with my neighbor who tried to start his diesel focus one day.
Even jump starting with another battery didn't solve the starting problem.

You could also check the EGR valve for damages and if you want to save a couple of bucks, then go in for used parts for the focus from Good used Focus Stuff

sound like glow plugs wires harness disconnected or wires could be damaged during the transmission installation since transmission has to be remove when replacing flywheel.

Relay or control module?

Motorcraft Glow Plug Relay 7 3 PowerStroke DI Turbo Diesel

Motorcraft Glow Plug Control Module

Glow plugs do not "fire". You may be confusing the function of glow plugs as analagous to spark plugs in a gasoline engine; the purpose of glow plugs is to heat the air-fuel mixture to a temperature that will support the diesel auto-combustion process. The diesel process is not one in which the air-fuel mixture is ignited via spark like a gas engine; rather, the air-fuel mixture undergoes much higher compression and spontaneously explodes, generating the combustion in a self-sustaining manner. High compression produces much higher heat, but before it can begin, heat must be introduced into the system to get it started.

If you're having sluggish engine performance from your diesel engine, you may have fuel system issues such as fuel pump failure or fuel line restrictions (including fuel filter or strainer clogging), etc. At the "worst" end of the spectrum, one of more of your fuel injectors may have a problem - the fuel injectors on the Powerstrokes not only inject the fuel into the combustion chamber, but are also cooled and lubricated by the fuel - if the vehicle has ever been run out of fuel, the injectors may have been damaged and will need to be inspected for replacement.

The glow plug on key on,connects the glow plugs to the battery positive,and allows the glow plug to GLOW,and ignite the cylinder,for combustion.

Above the Relay Panel is the Auxiliary Relay Panel. Has thirteen positions in it.
6 across the top, 7 across the bottom.

Across the bottom the Glow Plug Relay is the fourth one over from the left. It is Number 10.
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