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Why wont my glow plugs turn on?

Glow plug light wont light up inticating plugs are warm. Pulled wires off glow plug relay and cleaned them up. Started up and ran fine till I turned it off. Then had to pull wires and clean up before it started. Did this for a couple of days and then wouldnt do it at all. Replaced glow plug relay and still no luck. Retuned it for another glow plug relay and still nothing? Put old relay back in and got it to work and start for a day and now nothing again?

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6ya6ya
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Posted on Jan 02, 2017

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  • 140 Answers

SOURCE: How do you change the glow plugs and relay in a F350 1997

Hello, here is the proceedure. Any questions please ask. Good luck. CAUTION The red-striped wires on the 1994-96 DI Turbo engine carry 115 volts DC. A severe electrical shock may be given. Do not pierce the wires.

  1. Make sure the ignition switch is OFF.
  2. For 1994-96 engines, remove the valve cover.
  3. Disconnect the wire connector from the glow plug.
  4. Using a 10mm deep socket, with enough clearance as to not break or bend the wiring connector, unscrew the glow plug from the manifold.
To install:
  1. Place anti-seize on the threads of the glow plug and screw it into the manifold.
  2. Tighten the glow plug to 12 ft. lbs. (16 Nm).
  3. Plug the wiring connector.
  4. Connect the negative battery cable.
  5. For 1994-96 engines, install the valve cover.
0900c152801cd773.jpgFig. 4: Disconnect the wire, then remove the glow plugs as shown

Posted on Jan 23, 2009

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SOURCE: put new glow plugs in ran fine for 1 day now it wont start..

You may want to surf around on some of the powerstroke forums for detailed answers, but I know the powerstrokes use oil pressure to control the injectors so you may have some problems with the high pressure oil pump.
Again, it is just a guess. I just wanted to point you to some of the Ford Powerstroke forums which may be of much more help for you.
Good luck..

Posted on Feb 03, 2009

  • 102 Answers

SOURCE: 2002 Jetta TDI check engine light

very common for the harness that plugs onto the glow plugs to have too much resistance it will still work but will set codes

Posted on Mar 23, 2009

  • 43 Answers

SOURCE: where is glow plug relay on a 2007 f350 6.0

I can solve this problem for you but I need the right information. They have your truck listed as a 2003 F-350. Then it is also listed as a 2007 and want to know where the glow plug relay is. I need the correct year and model with the proper engine displacement.

Posted on Apr 14, 2009

steve_e_uk
  • 1675 Answers

SOURCE: How do i replace my VW SHARAN 02 glow plug relay.

the glow plug relay is a little black box normally located in the fues box, the relay regulates power to the glow plugs, if the relay is not functioning correctly the plugs will not heat enough or, you will have to allow a longer time to let them heat up, it acts like a switch as such, when you turn on your ignition it switches over to make a contact inside, which inturn starts the heating prosess of the glow plugs when they are at the correct tempreture or the onbored computer detects they are it then switches back , without it , say just using a fuse instead, your glowplugs will just get hotter and hotter till they melted, and no you dont have to change the glow plugs hope this helps, ime not good at explaining stuff in writing lol

Posted on Jan 30, 2010

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2 Answers

Glow plug light stays on, engine turns over but won't start


glow plugs dont last for ever
have them visually inspected

they need to heat up to spec or motor wont start

what motor or vehicle ?

May 31, 2016 | Cars & Trucks

3 Answers

Mercedes 300td wont start


It's likely a bad glow plug relay found on the left fender well. You may have bad glow plugs as well. You should hear a faint click when you turn the key to glow psn. . Open the hood and have someone glow it. The click should be abvious and the wires will run from the relay to the glow plugs. also obvious.

Oct 06, 2014 | 1998 Mercedes-Benz E-Class

1 Answer

Truck wont start, but only if you hear a click


I copied this from my GM service manual for 1982 6.2 diesel.

1. If the glow plug relay is not clicking on and off then turn the ignition to the RUN position and connect a 12V test light to ground and touch the pink/black wire in the glow plug relay connector.

2. If the light is off repair the open cicuit in the pink/black wire to the splice.If the light is on then touch the light blue at the glow plug relay connector.

3. If the light is off replace the glow plug relay. If the light is on, disconnect the connection at the thermal controller and touch the black wire in the connector.

4. If the light is off, repair the open circuit in the light blue wire from the thermal controller to the glow plug relay. If the light is on repair open circuit in black wire back to a splice. If no trouble is found replace the controller.



You should also get your hands on this Haynes book. Diesel Engine Repair Manual, part # 10330. Excellent coverage on the 6.2 and 6.5. In it, they say that early 82\'s have a hole at the number 2 hole on the pin connector of the wire harness for the thermal controller. this allows dirt in there and corrodes the pins. Remove the connector and clean thoroughly the pin area on the connection and controller. Seal the hole with some silicone. If things are still acting up, replace the wire harness connector.



Hope some of this helps.

Jan 19, 2014 | 1983 GMC C1500

1 Answer

A Deisel jetta need to replace glow plug rely ,,where is it..?? And its very very hard to start ..is this going to do it and how do you know if the deisel is worth keeping it has like 300,000 _ thanks...


not always the golw plugs can be bad and the engine can be low on compression. does it start alot better if you add a gallon of kerosene to 5 gals of desiel? Or a quaart of gas? the glow plugs can be checked with a test light the connectrs are in plain veiw and the wires going to them are big. Follow the wires back to the relay they go straight there, the relay is real close to the battery as it draws alot of power follow the big wire on the battery that doesn't go to the starter and thats the glow plug relay. they last good but the connections get dirty, reconnect all the connectors on itand see with the key on if the glow plug light comes on on the dash that wire that lights the light is the same wire that lights the light fires the glow plugs. You can take the wire off the glow plug( you need to do it anyway it's a yearly service anyway and with a test light connected to power touch the disconnected glow plug with the lights probe and the light should light, not all of them are likly to be bad but if you find two or more just change them all as the ones that aren't out are likly to fail anytime and if you want to drive though the winter you need all the help you can gt. the battery cables and the one going to the glow plug relay are likly to fail at the battery so go over this good It might start fine with just two glow plugs working I'd pick the two center cyclinders or the two outboard ones as once the engine starts it'll keep running long enough to start the other ones. low voltage as your cranking can effect the glow plugs but the relay is suposed to turn the glow plugs off at cranking and time out after they've been on long enough. dirty connections are almost always the problem so clean everthing before you replace anything. Needs cleaned before yu put on new parts anyway and the glow plugs need to be taken out with the right tool or you may end up with a broken off glow plug in your cyclinder head.

Oct 01, 2010 | 1991 Volkswagen Jetta

1 Answer

Tried to start 2004 f250 with out glowplugs now it wont start. checked fuse still wont start


glow plug light and glow plug are not on same system
check at gow plug conection (top of valve cover both side
follow from relay front valve vover right side silver box)
power 12 volts on all 4 wires in both conector left and right
if not replace relay if 12 volts relay ok (test light clip on ground)
then check glow plug (test light clip on positive ) touch wires going
to glow plug should light up if ok (quick test ) if any fail replaced
if all seems ok look at the oil injection system most common
problem with these motors I have yet to replaced a glow plug or relay

Sep 30, 2010 | 2004 Ford F350

2 Answers

1997 VW JETTA DIESEL GLOW PLUGS


The glow plug relay is responsible for the duration of glow plugs, this needs to be the starting point. You should get a 12v out for so many seconds when ignition is switched on.
I have taken the cover off relays in the past, cleaned up the internals, sprayed with circuit cleaner and got plenty more years out of them, worth a try.

Nov 21, 2009 | 1997 Volkswagen Jetta

1 Answer

VW passat glow plug problem


Yes you have a defective glow plug relay if you have your owners manual you can find it and replace it, the unit also has a timer on it, if you don't have a book look for the glow plugs and follow the wires from the glow plugs to where they terminate there you will find the relay unit and replace it, to test the glow plugs you remove the wires and test each plug by pulling off the wire and with a cheep ohm meter touch one end to the glow plug and one end to ground if it swings almost al the way over it is ok, if it dos not move then that glow plug is bad. if you find 2 or more bad then replace them all, and if a glow plug has shorted and caused this problem you will have to replace the glow plug relay. Good luck.

Jun 19, 2009 | 2003 Volkswagen Passat

1 Answer

Glow plugs causing starting problem


if you need connectors and terminals for the glow plug connections under the valve cover, Ford sells then so you don't need a whole $600 harness.

info for your use

Section 03-07B: Glow Plug System 1996 F-250, F-350, F-Super Duty Equipped with 7.3L Diesel Engines Workshop Manual
DESCRIPTION AND OPERATION Glow Plug System The 7.3L diesel engine uses a glow plug system which preheats air in the combustion chamber to improve cold engine starting. The system consists of eight glow plugs, the glow plug control module (12B533), powertrain control module (PCM) (12A650), engine oil temperature (EOT) sensor and barometric pressure sensor (BARO sensor) (12A644). The glow plug system is electronically controlled by the powertrain control module. The powertrain control module energizes the glow plugs immediately after the key is placed in the ON position and then determines how long the glow plugs will be on according to the engine oil temperature and the barometric pressure. The required time for the glow plugs to be energized decreases as the engine oil temperature and barometric pressure increase. The glow plugs are self-regulating, and the powertrain control module controls relay ON time. The powertrain control module protects the glow plugs by energizing them for short durations if the battery voltage is abnormally high.

Possible Causes: Insufficient glow plug ON time will not allow enough heat to accumulate in the combustion chamber to easily facilitate starting. If the glow plug system ON time does not meet any of the specifications in the accompanying chart the problem is most likely a faulty wire harness connection, ground connections or glow plug relay.

If the glow plug resistance to ground is high, the most likely causes are an open UVC (under valve cover) harness or open glow plug.
--------------------------------------------------------
Relay Operation
Install a DVOM on the glow plug feed side of the glow plug relay (large stud with two wires connected). Turn the ignition key to the ON position but do not attempt to start. Note the time in seconds from when the key is turned on and the glow plug relay energizes until the glow plug relay de-energizes. The glow plug relay makes a loud click noise which is easily heard when it energizes and de-energizes. The dome light will dim and the dash voltmeter will dip when the glow plugs are drawing current from the battery. Compare the times measured to the table (time will be affected by engine temperature, battery condition and vehicle altitude). The voltage at the glow plug feed terminal may vary from 9 to 12 volts depending upon battery condition.
--------------------------------------

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If battery voltage not present check for B+ at power supply terminal (terminal with single large wire). Power for glow plug power supply is supplied from starter relay through two fusible links at solenoid.
Glow Plug Operation
Disconnect all of the glow plug/injector harness connectors from the valve cover gaskets. With the pigtail installed, measure glow plug resistance to ground (preferably B-). A resistance measurement of .1 to 6 ohms indicates a good glow plug.



Glow Plug Harness Continuity
Measure for continuity from the connector harness to the glow plug feed terminal on the glow plug relay. Resistance should be less than 5 ohms.
Incorrect measurements will result if all glow plug/injector connectors to valve cover are not disconnected.

---------------------------------------------------
Glow Plug Relay The glow plug relay (12A343) has a plastic base and two mounting bolts. It is operated by the powertrain control module (PCM) (12A650) which senses engine oil temperature, PCM voltage and barometric pressure. When the engine oil temperature or the barometric pressure is low, the PCM activates the glow plug relay and the glow plugs. If the PCM voltage is too high, the powertrain control module deactivates the glow plug relay and the glow plugs immediately energize for a shorter duration, decreasing the modulation of the duty cycle.
-----------------------------------------------
Glow Plug Removal
  1. stj~us~en~file=ani_caut.gif~gen~ref.gif WARNING: THE RED-STRIPED WIRING HARNESS CARRIES 115V DC. SEVERE ELECTRICAL SHOCK MAY BE RECEIVED. DO NOT PIERCE.
    Remove valve cover (6582). Refer to Section 03-01D .
  1. Disconnect glow plug electrical connector using a pair of pliers.
  1. Remove glow plug using 10mm socket.
  1. Clean and inspect glow plug tip for damage. Replace if damaged.
Installation
  1. Install glow plug and tighten to 19 Nm (14 lb-ft).
  1. Connect glow plug electrical connector. Make sure glow plug wiring is routed to avoid moving parts.
--------------------------------------------------------------
Glow Plug Control Glow plugs are used to warm the cylinders to improve cold-engine starting. The PCM uses the engine oil temperature (EOT) sensor and barometric pressure (BARO) sensor to determine how long the glow plugs will be on. The PCM energizes the glow plugs longer if the engine is very cold or if the barometric pressure is low at high altitudes.
The PCM controls the relay that supplies power to the glow plugs with the glow plug control (GPC) signal. When the GPC signal is grounded by the PCM the relay closes, turning the glow plugs on.
The glow plugs are controlled by the following sequence:
  1. PCM energizes the glow plugs.
  1. The PCM energizes the glow plugs immediately after the ignition is placed in the ON position.
  1. The PCM then determines how long glow plugs will be on based on EOT sensor and the BARO sensor. The required time to warm up the cylinder decreases the engine oil temperature and barometric pressure increases at low altitudes.
Glow Plug Lamp Control The glow plug lamp (GPL) signal controls the WAIT TO START light located on the instrument panel. This light is used to indicate when to start the engine. The cylinders are being warmed by the glow plugs during and after this light is lit. The PCM energizes the glow plug lamp longer if the engine is very cold or if the barometric pressure is low.
When the GPL signal is brought low, the "Wait to Start" lamp is turned on.
The glow plug lamp is controlled by the following sequence:
  1. PCM lights the WAIT TO START light after a key on reset occurs.
The PCM determines the glow plug lamp activation time based on engine oil temperature, barometric pressure and battery voltage.
  1. PCM turns off the WAIT TO START light.
The glow plug lamp is turned off when the timer counts to the number of seconds specified by the PCM. The glow plugs will normally remain on longer than the "Wait to Start" lamp.
-----------------------------------

Mar 14, 2009 | 2004 Ford F350

1 Answer

Vauxhall vivaro wont start cold


Sounds like a faulty cold start assistor. On top of the engine you will find an aluminium housing with four things that look like glow plugs screwed into it. These 'glow plugs' are only available complete with the housing fron Vauxhall. Approx £70 +
Airbag light is probably a fault with the seatbelt pretensioner.
Check the wiring under the seats for damage or perhaps the plugs have pulled apart.

Oct 30, 2008 | 2002 Volkswagen Eurovan

1 Answer

2002 Jetta TDI has no power to glow plug buss at startup


replace the relay but check connections first as often connection get hot and corroded.failing which buy a push button switch use a relay and and some heavy wire to and from relay to the heaters and work them manually.you could try seperating the relay and cleaning the connections inside.

Oct 22, 2008 | 2002 Volkswagen Jetta TDI

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