Flickering lights, clicking from dash?

Army_Tanker

Well-known member
Joined
Jul 17, 2001
Location
Ft. Hood, Tx
TDI
2001 Blue Jetta
My car has started acting funny lately. For about 5 minuites after starting it the lights will flicker and there is a clicking noise from under the dash. Revving the engine up helps solve he problem, but when the rpms drop back down to the idle range it starts back up again. Like I said after driving for a few minuites the problem goes away.

Could this be a bad relay? I don't think it is the infamous 109 because I have had that problem and the symptoms are different this time. Any Ideas?
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
does it do this at idle?

It sounds to me like the normal operation of the afterglow function. Below 2500 rpms, the glowplugs will function to aid in combustion. If you rev the engine above 2500 rpms, the relay clicks off (hence the clicking sound), and the glowplugs shut off. Since the glowplugs draw so much current, the headlights may go bright/dim when relay clicks on/off. Avoid engines speeds above 2500 rpms until the engine warms up to operating temperature.
 

Army_Tanker

Well-known member
Joined
Jul 17, 2001
Location
Ft. Hood, Tx
TDI
2001 Blue Jetta
The thing is that it doesn't just click off and back on when the rpms drop back to idle. When I am sitting at a red light or something the dash lights and headlights lights are flickering really bad. People in other cars start looking at me funny. and the noise from the dash is going "click-click...click-click...click-click" Whatever relay controls the afterglow must be malfunctioning, anybody know which relay it is?
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
Okay, your updated description does not sound like the afterglow function. You probably have a faulty relay that needs to be replaced.

I believe the glowplug relay in pre-2002 cars is relay #180. I also think this has been replaced by an under-hood relay in the newer cars. Again, i'm not 100% sure about this.

If you have a Vag-Com, you can view one of the measuring blocks, i'm not sure which one it is off the top of my head, and view glowplug status in binary format (1=on, 0=off). If the binary values are changing while your relay is clicking, then your problem is in the glowplug relay. If the binary values stay the same while the relay is clicking, then the problem is not in your glowplug relay.

Hope this helps.

[ September 26, 2002, 10:48: Message edited by: VeeDubTDI ]
 

Dean_S

Veteran Member
Joined
Mar 29, 2001
Location
Lawrence Kansas
TDI
BMW 535d x-drive
What was described is also consistant with low voltage. The statement that reving the engine supports this as the alternator will be able to put out more power. But the fact that there was no statement that the engine was not cranking over easily is puzzleing.

There could be a bad relay or ''ignition'' switch with burnt contacts.

Perhaps the battery electrolyte levels should be looked at.
 

Army_Tanker

Well-known member
Joined
Jul 17, 2001
Location
Ft. Hood, Tx
TDI
2001 Blue Jetta
The glow plugs warm up fine and the engine cranks like a champ so I don't think there is a problem with the battery. The clicking is what points me towards a relay or bad connection of some sort.

I know the sound of the afterglow "click" when the rpms drop, I have had the car for over a year. The thing is that this is the same sound and happens at the same time, but over the past 2 or 3 days it has just seemed to go haywire.
 

tongsli

Top Post Dawg
Joined
Jan 31, 2000
Location
Baltimore, MD
TDI
2000 Jetta TDI, 2004, Jetta Wagon TDI PD
I believe the glowplug relay in pre-2002 cars is relay #108, but i'm not 100% sure. I also think this has been replaced by an under-hood relay in the newer cars.
<font size="2" face="Verdana, Helvetica, sans-serif">Lawson,

It's 180 and yes it's a control module in the OEM plenum.

Probably a relay. Remove the front trim covers and metal plate at your knees so it looks like this...



Then, you can listen and diagnose the clicking relay.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
Thanks for the correction Lito, i've updated my previous post.
 

Army_Tanker

Well-known member
Joined
Jul 17, 2001
Location
Ft. Hood, Tx
TDI
2001 Blue Jetta
Yeah, I know how to get to the relays, I have replaced #109 on another TDI, I will check out relay #180 and see if it is the source of my problems. Thanks for the help.
 
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