[Vwdiesel] slow glow plug relay, no glow light when engine is warm

[lbaird119 at aol.com]

As I recall, the relay will actually stay on for the maximum time (which can vary) if you turn the key to the on position and wait.  Listen and you'll hear it click off.  The light is the variable, where it's on when cold and on very shortly or not at all when the engine is hot.  I know some come back on for a time after starting.  Not sure if all do, some do or it's just a rumor...  Never really checked.  :-)

  If your relay is actually not coming on at all when the engine is warm, then something isn't working correctly and as Roger pointed out, that could be the sender being out of spec or a relay that's snippy about what resistance it wants to operate properly.
     Loren



-----Original Message-----
From: Roger Brown <r.c.brown at ieee.org>
To: vwdiesel <vwdiesel at vwfans.com>
Sent: Sat, Sep 6, 2014 10:26 am
Subject: Re: [Vwdiesel] slow glow plug relay, no glow light when engine is warm


One thing you might want to do is to hook up an indicator light on the glow plug 
us or 
usible link if at all possible.  You should see the glow plugs getting power 
ven at a 
arm start, although the GP dash light may not be on.  I used a pair of lighted 
indshield 
asher nozzles and ran the light wires down to the glow plug relay.  Actually, I 
eed to 
odify that to put one nozzle light on each side of the fuse so I can see if the 
use ever 
urns out.  But with the actual glow plug power indicator, you can use that as 
our clue 
hen the crank the engine over, let that light stay on for a while before 
urning the key.
And if you are not getting power to the GPs at a warm start, you may have a 
laky relay.  
ee the testing info below.  I find the real Bosch brand relays do the best job, 
he off 
rand relays may work some of the time, but at the fringes, they may not.  One 
xample is 
ith temp sender input.  If that is out of the range the relay is expecting, it 
an do 
trange things.  I've had relays that fail to turn on when high temp input is 
resent or 
urn on and off erratically.  The Bosch relays seem to "do the right thing" in 
ll cases.  
hey'll have a maximum time and a minimum time that they will run regardless of 
he engine 
emp.

n 9/5/2014 12:22 PM, Roger Brown wrote:
 Some ideas below:
     http://www.4crawler.com/Diesel/CheapTricks/GlowPlugs.shtml
     http://www.4crawler.com/Diesel/GlowPlug.shtml

 Could be an intermittent connection in the socket or perhaps the connection to 
he 
 temperature sender on the head.


 On 9/5/2014 12:21 PM, Marciano Pitargue wrote:
> It never rains in San Jose, CA.  But last winter, it did a bit, and my fuse
> box got wet due to a poor seal of the windshield.  (Fixed that I hope.)
> So, I ended up changing out the (original ?) crusty metal bodied (slow)
> glow plug relay in my 1980 caddy with a plastic bodied glow plug relay
> replacement.  Supposedly, this glow plug relay is for the slow glow plug
> relay circuit that were on the 1980 vw diesel vehicles.
>
> Now, when the engine is cold, like first thing in the morning, I get the
> nice warm glow of the glow plug light.  However, when the engine is up to
> temp, no glow plug light, hence hard starting if the truck sat for about 30
> minutes.  Before the fuse box wet event, it always used to light up no
> matter the temperature of the engine.  And it seems the glow plug light
> accurately tracks the power to the glow plugs.
>
> Checked the grounds for the relays for corrosion.  They seem clean.  One
> thing I noticed is that when the glow plug light doesn't light, if I unplug
> and plug in the (new) relay, sometimes the glow plug light lights.  I
> suspect that that the glow plug relay isn't correct for my slow glow plug
> relay circuit.  Or maybe I missed some ground points (I found 2 circular
> fobs where a bunch of brown wires connect to.)
>
> Any advice from the group to address this issue?
>
> Thanks in advance.
>
> Marciano, driver of "slo-mo smokey"
> _______________________________________________
> Vwdiesel mailing list
> Vwdiesel at vwfans.com
> http://www.audifans.com/mailman/listinfo/vwdiesel

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