Having wrecked the glow plugs leading to an expensive head off job, I have finally decided the heater/timer unit in my 24v. 1982, bj42 has got to go. It was damaged in its rolling down the Pyrenees but is now proving to be too unreliable. My question to all you experts is, can I simply utilise just one relay to supply the super glow plugs with 24v. then switch the relay off after an appropriate time by means of a Wilson switch. At the moment I have 2 relays which should supply the plugs for differing times , one of them reducing to 0v whilst the other reduces to a lower voltage for a longer time. Does that make sense? I attempted to monitor the sequence and values from each relay but the results were not conclusive. Has anyone else done the same? It would be a simple thing to check if I had a working timer unit. I suppose my real question is, is it safe to apply 24v. to super glow plugs for let's say 20 secs.
dual relay super glow Wilson switch conversion
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John in Utah
SILVER Star
Your superglow plugs are 14V, so I’d say 20 seconds at battery voltage is too long. You might have success dropping the input to your plugs with a diy voltage divider, but I think the best/simplest approach is to get 24V plugs and run a direct line to battery voltage.
I have a single beefy relay on the firewall that is activated by a momentary switch in the cab. I can get you some pictures/diagrams of it (in fact I think I already promised you that!)
I have a single beefy relay on the firewall that is activated by a momentary switch in the cab. I can get you some pictures/diagrams of it (in fact I think I already promised you that!)
jim land
SILVER Star
I use the big factory relay on the radiator support. , direct 24v with a momentary switch, also use the factory glow light on the dash
jim land
SILVER Star
jim land
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Decision made. I plan to energise the 2 relays using a double pole double throw ( DPDT ) momentary switch ( centre zero ) feeding 24v to relay 1 for 5 secs. then switching 24 v to relay 2 for 15 secs. approx.Using the original relays and wiring, this should feed 24v to the glow plugs for 5 secs then 14 v to the plugs for 15 secs. If she fires and runs smoothly after 5 secs I may not need to employ the second relay. I shall wire in the glow plug lamp just for a bit of visual security .The good thing is Using a momentary switch means it will always return to zero volts so I shouldn't be able to make the same mistake twice.
