OK
So
I have a 1984 Rabbit 1.6 Diesel
and I ma having issues with the glow plugs not working
I put in a new relay last week
as I thought that this could be the culprit.

usually have my block heater on a timer and plugged in so I can fire her up in the AM

the glow plugs don't seem to be glowing
they are about 1 year old all replaced at once
the thing is that my dash has some weird ground or short issues , so my glow plug light only comes on when the car is parked in the sun a and it is like 90° +F

so usually I turn the key on and wait like ~ 15 seconds

the new relay is said to be a 7 second relay
it was firing up very nice

but yesterday no go
unlpulleg the relay and the X-Relay a few times

today I finally hooked up my battery charger and cranked her for like 30+ seconds til she sputtered to run...
after about 20 minutes of fiddling - I was 10+ minutes late for work...
all in the dark at 610 am

same tomorrow I hope she starts

any ideas?

thanx
-- Ian

FKH161
thanx (as always) for your replies and great insight.

I realize that the dash light is just a representation of the physical glow, and has nothing to do with the glow plugs actually glowing or not- it never bothered me, just weird .
I have other dash panel light issues, like my instrument lights used to work intermittently, but went out - no worries I used some blue LED "accent" lights I can see my dash at night just fine.
also my turning indicator light sometimes blinks - sometimes not...

I don't have a test light... I guess I need one

but
I suppose I could use my multimeter, to see when juice is flowing and for how long...

so
what I did not mention is that I had already pulled the blue wire from the temp sensor on the engine, as
my buddy Justin at Grease Works mentioned that if I did this the glow plugs would glow at full power, and duration - since the relay would sense a cold engine

the other things I did were to cut out the "quick disconnect" that went from the starter to the glow wires leading to the relay, as it was old n funky.
also I cut out the wire that went from the 8 gauge pre "quick disconnect" to like 12 gauge then back to the thick 8, I think there was a fusable link, but the wire looked like it had gotten hot... was a bit crispy looking

what I found as I was attempting to remove the spaded wires from the back of the relay plug socket was that the red & black striped (smaller 12g) wire looking like it lead to pin # 50? was loose, and not staying in place, like the click lock for that spade was missing...
I check all the other spades and wires, looked good no corrosion and solid connections - I used some dielectric grease to help with conductivity

Justin mentioned he thinks the 50 pin is a ground wire as well, I am hoping that this may have been the culprit.

I'll need to check on the glow time and report back

thanx
-- Ian

so,
today - this am it seemed not to glow, at least 2 x I tried with the Key
I had gotten a piece of 4 gauge welding wire, in order to jump the relay and connect the glow plug bridge to the battery direct, as you suggested.
she fired right up
(my block heater is on)

I got a test light today after work.
w/o the temp sensor connected
the glow seemed to be infinite- but after about 30 seconds I turned the key off
I repeated this a few times
same results

I also tried it with the temp sensor wire connected.
the glow was for about 10 seconds or so

what I found interesting
was that
I also started the car a number of times, and both with or w/o the temp sensor even after the engine was running for about 5+ seconds.

I also noticed - I I listened very carefully I could hear the relay - click on and off.

also this was with my battery charger hooked up on fast (10 amp) charge
I wonder if there is any relationship to low voltage or amperage and the relay not clicking on?
I had my battery load tested and it seems that I should replace it - this because I have had issues with my "accessories" and grounds, there is a new Reman Bosh Alternator, installed after issues on long drives where my battery was dead. I have (driving) Fog Lights, and a "band" heater on my fuel filter for cold weather anti gelling, as well as a stereo with a tiny 6" powered subwoofer.
during long 4 hour drives, with all my lights fuel I was running at a net deficit.
I have since re-grounded all the grounds direct to the battery, and gotten a new 4 gauge body ground cable, as well as tied other body ground points back the the battery.

any how
I am wondering if there could be any voltage or amperage related issues with the relay.
I understand that if there is enough juice to crank the engine there is also enough to glow the plugs.

I am planing on getting a new higher cold cranking amperage battery...

we have used an induction meter to check voltage at the glow plugs - it appear that is is fine.

that's it for now

thanx for your help

-- Ian