New glow plug relay is not cool! Battery dies on short drives.

[cousindave76]

I have searched the forum for my problem but I can't find anyone with quite the same issue. Lot's of folks with non working glow systems or glow systems that never turn off. Not quite my problem.

Car: 1983 300SD 240k, runs smoooooth and awesome!

I replaced a bad glow plug relay box. It works great. Glow light on the dash cycles on, then off and the engine starts very nicely. Trouble is, the glow plugs do not shut off for 3 minutes, no matter what. I have read that the new relays have this 3 minute shutoff time as a new and improved built-in feature(do not want). I have recently moved within 4 city blocks of where I work. So the time it takes me to start the car, drive to work and shut it off, the glow plugs will have just turned off and the battery never gets an opportunity to recover since the alternator is giving all it's 55 little amps to the glow plugs. Doing this short trip a few times, the battery finally can't keep up anymore and I get stuck. If I drive longer distances I don't have this problem.

Also, if I let the car warm up all the way, turn off the ignition and then turn it back on immediately, the glow plugs will stay on for a full three minutes again. Heck, in this Texas heat, the glow plugs are not even needed when restarting after it's been started once that day.

I never had this trouble with my old relay because once the car was started the relay turned off and the charging system was happy.

Is there any part of the glow system that should detect the engine temp and shutoff the relay? Perhaps mine is malfunctioning? If not, is there a way I could install a manual shutoff switch on my dash that I could just turn the relay off after I start up? I want this relay to function as my old one did before it decided to depart this world.

Thanks much for any ideas!