Where the wiring harness plugs into on vw jetta with reverse sensors

Those sensors wouldn't affect power to the injectors.

You need a voltmeter, it's an electrical problem, so you need a digital volt/ohm meter (DVOM), or also called a multi-meter, and digital because many car circuits that are computer related operate at very low voltages or power demands, from milliamps to thousands of volts, like the ignition delivers to the spark plugs. So you buy a cheap multi-meter, then you also need a wiring diagram for your car to see how the fuel injector circuit works. but start there where you plugged in the new injector harness.

You are looking for power to the injectors, with key on. The injector harness has 8 wires; each injector has a power wire and a ground wire, so 4 of the wires in the harness should have power. At least on most American cars, the injector works by having the ecm control the ground for the injector . The power is constant. It is only when the ecm momentarily internally grounds the injector circuit that the injector fires. On your VW, the injector power wires and ground wires both go to the ecm.

remove covers around column follow wire going to electrical part of switch and remove small set screw to switch pull down unplug harness reverse order to install

The fans are run by rad temperature, not engine temp on a VW.Somewhere on the rad you should see a wire harness plugged into it.That is a thermo-switch which turns the fans on and off based on coolant temp in the rad. My car is a lot older than yours but this switch is virtually hidden on the bottom driver's side of the rad. It has 3 wires going into it.There could also be another sensor attached to the engine block or head to monitor engine compartment temps after engine shut off. This will turn the fans on or off as well based on air temp in the engine compartment.

Before you invest in a long drawn out Glow Plug replacement etc. A little known issue occurs on the ALH TDI engines. The temperature sensor sending unit. A small blue module that plugs into the coolant hose assembly will cause a P error on the glow plugs that is nothing to do with the glow plugs at all. The part fails and sends a temp error to the engine computer. I tested all the coolant glow plugs, engine glow plugs and glow plug harness and all worked fine. One of the test procedures for the glow plugs is to undo this sensor that will force the glow plugs to come on no matter what temperature. This confirmed my GP system was functional and the sensor was bad. I purchased the part from local VW dealer for $33 US and installed and it is fine. Dependent on your model it can be square or round. The link to this part for your car is http://www.partsgeek.com/catalog/1997/volkswagen/jetta/body_electrical/water_temperature_sender.html

Be sure to have VW Pentosin coolant on hand to refill coolant system as you will lose quite a bit when removing this part. It is located slightly behind the coolant glow plug assembly.. This is the round ones not the ones on the engine block at top.

Be sure that when you replace it you put in a new rubber gasket seal.. its a round rubber seal that should come with your new part. Dont reuse the old one or you will have a leak.

There is a c-clip that holds this in the hole you slide that clip off and wiggle the sensor out. Coolant will run out of the hole, so do this outside. The sensor is easily pulled out. You will need to insert the new part in teh same hole with new rubber gasket and replace c clip. Then plug in wiring harness and you should be good to go.

slide the seat right forward and undo the two bolts in the slider then slide right back and undo the front twothen lift it out.when you put it back make sure the bolts are tight....

this is a common problem for these cars glow plugs go bad like spark plugs however the smoke would lead to bad mass airflow meter. it is not telling ecu corrcet miss. disconnect mass airflow meter. when cold see if this makes it start better. it should would means you need new m.a.f. glow plug issue take a test light place clamp on positive of battery then pull off glow plug connectors place tip of test light on glow plug the bad one will have a dull light unlike the good one which will be brighter. will need new plugs and wire harness four **** connectors and wire striper and crimper will fix concern good luck

There is no DTC codes for VW 638, your going to need to get the right code There is a P1638 and that is Data Bus Power train missing message from clutch control. which means there is not communication from the TCM to the clutch control. (there is no signal from the Sensor to the ECM) replace sensor and check the wire harness. Good luck and hope this helps. 

If the mass flow sensor was bad, the check engine light should of came on giving off an engine code. To remove the mass flow, disconnect battery neg cable, then pull of the wire harness and pull out mass. You will probably have to remove the air intake hose.

Check for a switch at lower part of rad. Should see a wire harness & plug on a sensor at bottom of rad. This sensor/switch also operates fan on/off according to coolant temperature. You may need to disconnect battery to get at it safely.