1010 glow plugs burn out!!!!

[robk]

Here is one guy's observations about redesigning VW glow plug wiring:

IMHO there are several weaknesses in the original VW IDI glowplug harness, including:

the full amperage of the circuit (50 amps or so) passes thru the firewall and thru the connectors in the fuseblock
the copper buss bar makes removing the glow plugs a pain since you have to completely remove the 8mm nuts
the copper buss bar makes troubleshooting a pain since all plugs are connected in parallel
the 50A fuse is prone to hairline fractures that takes out all your glowplugs
the glowplug relay itself is *extremely* expensive
the length and gauge of the factory wiring results in a reasonably significant voltage drop to the glow plugs... I've measured below 9V at the plugs when the battery was delivering 12.5V




Ergo, this design has the following features:

el-cheapo garden tractor relay carries all the current and protects the contacts of the expensive glow plug relay
all the heavy duty current travels via short wires in the engine compartment to minimize voltage drops
all the heavy duty current travels via over-designed wire gauges to minimze voltage drops
separate fuses provide individual protection and prevent all plugs from being disabled at once
separate and easy-to-remove fuses make it quick to continuity or current-test each glow plug individually
color-coded wires make it easy to trace which glow plug is which
modified connectors at the glowplug allow removal without removing the 8mm glow plug terminal nut