glow plug timer relay 2.5 dse

hello lads.after attacking my heater o-rings i,m now on a mission to solve my starting problem.i was told by the previous owner the timer relay(glow plug)is knackered?is there any way of checking this before i fork out £60 for a new un.i,ve read about 12 volts at the glow plug?is this a constant 12v or just while the timers doing its job.where abouts on the g/plugs do i check for 12volts.cheers craig

bart2181 said:

hello lads.after attacking my heater o-rings i,m now on a mission to solve my starting problem.i was told by the previous owner the timer relay(glow plug)is knackered?is there any way of checking this before i fork out £60 for a new un.i,ve read about 12 volts at the glow plug?is this a constant 12v or just while the timers doing its job.where abouts on the g/plugs do i check for 12volts.cheers craig

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Remove control unit ( in ECU box behind battery) check for any sign of burning or bad connections. You should have power to the glow plugs only when the timer is on. Clip a volt meter probe to any of the glow plug terminals other probe to earth, switch ignition on you should have power to plug. If you have power, you will have to disconnect each plug and with one continuity checker probe to earth, touch plug terminal if no continuity replace plug. This can be done with manifold in place but is much easier with it removed.

cheers matey.i have 12v at the g/plugs terminals.the voltage is there for approx 8-9secs but the the heater light on the dash goes out after about 4secs?what do ya reckon.

bart2181 said:

cheers matey.i have 12v at the g/plugs terminals.the voltage is there for approx 8-9secs but the the heater light on the dash goes out after about 4secs?what do ya reckon.

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Having 12 volts at plugs means relay is ok. Don't know about lamp going out early. The plugs heat very quickly, so would not worry overduly about that. 12 volts at plugs does not mean plugs are working. Don't know if plugs are individually wired or bused if they are bused you will have to diconnect every plug or continuity through one will show continuity on all when they maybe faulty. If you get continuity plug ok, if not change it. If you are having start problems you most likely have a few plugs out.

ok cheers mate.so let me get this right the continuity check is the same has the voltage check.i.e touch battery earth and touch glow plug terminal with tester?i presume with the ignition off.thanks again craig p.s me and vehicle electrics don,t get on has you,ve probably guessed

bart2181 said:

ok cheers mate.so let me get this right the continuity check is the same has the voltage check.i.e touch battery earth and touch glow plug terminal with tester?i presume with the ignition off.thanks again craig p.s me and vehicle electrics don,t get on has you,ve probably guessed

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My tester has a sounder for continuity. Continuity is not same as voltage check, you don't need a voltage to check continuity, all you are checking is that there is a circuit from the plug terminal through the plug to earth, so that when voltage is applied to the terminal the plug should glow. If there is no circuit the plug cannot glow. It is what is know as open circuit. Don't know what type of tester you have, but if you select OHMs any sort of reading indicates a circuit.

Personally I would not waste my time checking individual glow plugs, if one has failed the others won't be far behind, just replace the lot, job done! Oh and don't use cheapo replacements, they don't work well.