one of my 240d's had a glow plug relay box and the last glow plug isnt wired to the back wall with the 80a fuse (i dont have a glow plug light indicator on the instrument panel)
the other 240d has no relay box, the last glow plug is wired to the back wall with an 80a fuse and i get the glow plug indicator on the instrument panel
ive use the haynes and chilton books to try and figure this out to no avail
any suggestions?
I do not have the pic anymore but in some systems there is a "Reed Switch" inside of the Relay Box that protects it from over load. Typically Read Switches have a bi-metalic spring that when they get hot the different expansion rates of the metals causes the switch to open and cut off the electricity.
If you live in the US you might consider spending the $19.99+$7 shipping for the Factory Service Manual CD set. It covers whole car with the exception of Front End alinement specs and the rebuilding of Turbos and Transmissions.
The time, trouble and Money saved quickly pays for the Manual.
what i'm really wondering is if it's possible to bypass the relay box, whats going on with the other car that has no relay but the glowplug light indicator works
ive searched the forum, not finding the answer.
Both your 240Ds are 1979 models? they should both have the older glowplugs, wired in series. The relay is below the dashboard. It provides power to the glowplugs and to the indicator light.
The one without the glowplug light probably has been converted to newer glowplugs.
Both your 240Ds are 1979 models? they should both have the older glowplugs, wired in series. The relay is below the dashboard. It provides power to the glowplugs and to the indicator light.
The one without the glowplug light probably has been converted to newer glowplugs.
both are 1979s, and the one with the relay in the engine bay has the newer glow plugs but no wire connecting to the back wall near the 80amp fuse.
does it need that wire?
The new plugs don't need that wire to the back wall, because all glowers are powered individually from the glow relay. The 80A fuse is in the relay. There must be individual wires to each glower.
With the older Loop/Filiment style Glow Plugs there is 3 types of ways they work.
The one with the Big Knob you pull out "Gorilla Knob" has no relay it is the Switch itself. and it has a thing on the dash nick named a "Salt Shaker" that you watch glow to see if you GPs are Glowing.
The next type has a smaller pull Switch but you also need a key. The Salt Shaker is gone and I believe it has a light. That one has no Relay and is just a switch.
The next type I believe is just Key, Relay, and Dash Light. However there is at least 2 types of Relay Boxes. Depending on wich one you have it may have a fuse.
Part of the reason there is not a good DIY troubleshooting on them is that the three systems operate differently and with nothing to go one it is difficult to identify what system you have.
As I said it is best to have the Factory Service Manual CD so that you can identify the system you have and follow the Troubleshooting steps that they show for your particular syste.
Or just toss the whole older system and up date it with a kit.
The W123 has no salt shaker anymore. The 1979 model only uses the key to glow and start. It has a relay to power the plugs and the light. The problem here is that one of the 1979 240Ds doesn't have a original glowplug system.
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