Cold Weather= No headlights, Heater Fan, Glow plugs, Seat Heaters...

On my wife's 2003 Jetta TDI wagon in ambient temps say in the teens or colder on cold starts the glow plug dwell is very short. The car will turn over fine and eventually start but then the headlights don't work(low beams, high beams, DRL all in-op). Also the seat heaters don't work, the heater fan, the wipers, all do not work. When the car warms up or ambient temps go up you can restart the car and everything works again. Also if you turn the car on and off multiple times when it is cold eventually you can get everything to work.

Any ideas? My first thought is to check some grounds, but not sure where I should go to check.

Thanks in advance for help!

Travis

travist185 said:

Also the seat heaters don't work, the heater fan, the wipers, all do not work.

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My headlights never quit, but the rest sounds like the same issues I had a few weeks ago. Could be relay 100 has gone bad.

http://forums.tdiclub.com/showthread.php?t=454223

Search for relay 100 threads.

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Thanks Phaser. The load reduction circuit seems to be where I should start. I would call this issue intermittent because we have always been able to get these item to start working after turning the car on and off a number of times.

Wires, relays, switches? Look on top of the battery for any burnt circuits. Could even be grounds. There are several under the battery, one on the transmission housing, one under the plenum, several in the cabin (and truck I think)

The headlights work before the start, "BUT THEN" don't work?
The LRR contact in the ignition switch may not be returning to the 'run' configuration after the 'start' position.
Try pushing the key in towards the column with the engine running to see if the lights and such come back immediately.

It's an common B4 issue, and maybe a rarity in the A4, but it sounds suspiciously similar.

Lug_Nut said:

The headlights work before the start, "BUT THEN" don't work?.

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I don't believe this is the case. The headlights do not work at all until it warms up or if you turn the car on and off a few times.

Keep in mind all those are operated via a relay that is commanded by a controller, the switches in the car that you operate are not hard wired to these accessories directly, instead you are ordering a controller to trigger on/off certain relay to operate.

You are cranking your car too long, this causes the battery voltage to drop, and thus causing the controller to erroneously reset itself with wrong values.

Logic needs order, think of it this way, when your home computer stops responding to your key strokes, some implausible value got stored in a critical memory location, so you'd reset it and dump current values and reload with new and correct ones, and things start working again.

Make certain you have a healthy battery, and when it is cold even a good battery on my 04 did not resolve my stating issue, I installed a coolant heater, and that helped.

If you were to put on vcds after one of those cold starts, you'll notice a sea of red text, from controllers.

First time I came across this with my 04, I had a similar experience, one was the passenger rear door will not power lock or unlock and the power window wont work from anywhere.( I had no VCDS then, and was new to VW)
So I decided to get a new battery for the slow starting, and the door/window problem went away, this got me researching..

By putting an intelligent controller between the switch and the accessory is great for diagnosis purposes, vcds can alert you to problems you did not know you had, some are important others not so much..like front side marker bulb circuit issues..it turned to be a loose socket on my 2012 Passat, and of course VCDS can issue outputs to accessories to test for integrity, by-passing sensors.

I hope this helps.

I had my VCDS plugged into this car last night. The left rear abs sensor is the only error found. Should I use the VCDS to cycle the different accessories and be looking for errors?

The battery is brand new oem last summer and it turns the car over quite quickly even when cold. I will test the battery tomorrow night, but I don't expect an issue. The glow plug light on the dash only comes on for a second when I know it used to remain on for longer especially when cold. It does take some time for the car to start because the glow plug dwell is so short. Once all other accessories come back the glow plug dwell is much longer and the car starts much quicker.

are you saying the dwell period is longer after the car had started than it was when cold and has been sitting for a while ? if so, note..the coolant sensor should be sitting in coolant, this tells me maybe it is not, low coolant level in system, and once the engine had started circulating coolant comes in contact with sensor and in your case it actually cools it, and the controller resets the dwell.(air warmer than liquid)

Use VCDS to measure the coolant temperature as sensed by sensor, compare it to outside temp.under engine-measuring blocks somewhere between 000-004, measure it before you start it and see once it started if it actually goes down before it starts to rise.

COLD weather relay issues, mine just wouldn't start at all if cold, not turn over, then turn signal went out, get under dash to relays , i repolaced the 53 relays for 6 bucks each and voila, all fixed, This is a recurring issue.