I was attempting a glow plug relay swap t
the existing forward relay is rubber bushed and taller than replacement piece procured from NAPA the rearmost ( closest to the cab ) looks like more of a match but during keying cycles the rear ward one " clicks " telling me its functioning while the front one doesnt did the boys down at napa screw me up here

as always any and all help GREATLY appreciated

99 Bone stock PSD 6 speed

 

Did you get the 109 or 110 from NAPA. The 109 had to be rotated to fit.

 

If you're wondering which one does what, the rearmost one is for the air intake heater and it won't turn on unless the engine is idling and it's cold outside. If the front one clicks, at least the ECM is commanding it to turn on.

Cody

 

That part # is GPR110 that i got

 

The system consists of:

• glow plugs (12A342).
• glow plug relay (12A343).
• glow plug module (if equipped).
• powertrain control module (PCM) (12A650).
• engine oil temperature (EOT) sensor.
• barometric pressure sensor (BARO sensor) (12A644).

The glow plug system is electronically controlled by the PCM. If the engine oil temperature is below 55°C (131°F) the PCM will energize the glow plugs immediately after the key is placed in the ON position. Then, depending on the readings from the engine oil temperature (EOT) sensor and the barometric pressure (BARO) sensor, the PCM determines how long the glow plugs will be on

<TABLE cellSpacing=0 cellPadding=3 width="70%" border=1><TBODY><TR vAlign=top><TD>2 </TD><TD>— </TD><TD>Battery feed post (12 volt) (part of 1825931) </TD></TR><TR vAlign=top><TD>3 </TD><TD>— </TD><TD>Glow plug control post from PCM (part of 1825931) </TD></TR><TR vAlign=top><TD>4 </TD><TD>— </TD><TD>Glow plug feed post (part of 1825931) </TD></TR><TR vAlign=top><TD>5 </TD><TD>— </TD><TD>Key power feed post

(part of 1825931)
</TD></TR></TBODY></TABLE>

 

And the IAH
Intake Air Heater Starting Aid System
The intake air heater starting aid system improves cold weather starting and reduces white smoke and odor during cold weather starting and on extended idles.

The intake air heater starting aid system consists of the following:

engine oil temperature (EOT) sensor
intake air heater relay switch
intake air heater element
intake air temperature (IAT) sensor
powertrain control module (PCM)
starter switch
Intake air heater starting aid system operation.

The system is activated by the PCM when the ambient air temperature is below 0°C (32°F), the engine oil temperature is below 55°C (131°F) and the battery voltage is above 11.7 volts.
The intake air heater will stay on for 30 minutes as long as the engine is idling and the above conditions are met.
The intake air heating system will only activate once per "key on event". If the heater is activated and the vehicle is driven, the heater will not activate if the vehicle is taken back to idle.
The intake air is heated by using a heating element mounted into the compressor manifold.
The intake air heater relay switch, located next to the glow plug relay switch, supplies power to the intake air heater element.

 

are the posts numbered 3 and 5 interchangeable ? as i assume they activate/switch the relay on and off?
im thinking its a low tech item adn because i assumed it was a high tech device i got over analretentive ??

TIA

 

Ones ground and ones hot. The circuit is energized to close the relay. It does not appear to matter which one goes where (3 & 5) after looking at the schematics.

Check across the 2 big post with a DMM and see if you are getting 12vdc and same on the two small post. If the engine has been run and oil temp is over 131* the pcm wont command the GP system.

 

My glow plug relay gave up the ghost last time I was out on vacation in Colorado.
High altitude + frost on windows = will not start = stuck in campsite =
I ended up moving the glow plug wires to the intake heater relay and it has been wired that way ever since. The relay is physically larger than the glow plug relay and it has to drive a herkin' huge heater element inside the intake manifold so it's more than adequite for the task.

 

Hey, it's like a built in backup. Kwik, it doesn't throw a code with the AIH disconnected?

 

No, it should not. And it is the best backup because it is sitting right there on mine, disconnected. I would use it in a heartbeat but replace as soon as practical. Kinda like a CPS.

Dan, I'm sure you just didn't end up there stranded without at least jumping the stock GPR. Again, the stock AIH relay is a gem of a spare GPR. That is why mine still resides there and my AIH port is my boost reference point.

 

If there is a code for glow plugs, the SES light stays out. You have my curiosity up now, so I will check it today.
The exact course of events when the relay failed is it didn't come on the first time, but after pressing the button a few times, I heard the relay come on and I managed to get it started. (For those of you who didn't know, I've disabled computer control of my glow plug system and installed a manual button. I don't like the thought of glow plugs running for two minutes after startup just to control a little smoke on a cold diesel engine.)
I knew what the problem was thanks to FTE and did the "relay mod" at the next opportunity. Once running and warmed up for the day who needs glow plugs.
The "stuck in campsite" scenario never really happened, but I knew it would if I didn't get the problem resolved. I would have jumped the GPR if I had to, but I was lucky that day.

 

OK yall, I have read and read and read and still need help. My 99 started having problems ever since I hit a big pothole about 2 weeks ago. I have replaced: all glow plugs, icp, ipr, cps, idm, intake air heater, intake air heater relay. It is totally intermintent, thought I was fine until the other day driving down the road and it had no power & would idle like crap when slowing to a stop. Almost thought it was going to die. Then about 5 minutes later it was just fine. It threw these codes when that happened:
P1249 Wastegate fail steady state test
P1211 ICP not controllable - pressure above/below desired
P0542 Manifold intake air heater
P0640 Manifold intake air heater

And this one about a week ago:

P0478 Exhaust pressure control valve high input.

I also have an exhaust leak somewhere below/ behind the turbo. I think it is just from the connection from the drive side exhaust manifold to the y pipe that goes to the turbo. But that wouldn't make it run like crap would it?

 

A 2 1/2 year old thread, you have been reading. I'm sure these guys will help you out.

 

fuhrung, welcome to FTE.
You really need to start a new thread.