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Wolfgang
Wolfgang, VW Master Technician
Category: VW
Satisfied Customers: 4538
Experience:  Senior VW Master Tech 15 yrs
19871424
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I have a 2003 vw Jetta 1.8t and the after run water pump is

Customer Question

I have a 2003 vw Jetta 1.8t and the after run water pump is not working. When I checked under the hood one time the wire harness had come off and must have gotten in the fans and tore the end off. I got a new end and spliced it in but it won't run
Submitted: 1 year ago.
Category: VW
Expert:  Wolfgang replied 1 year ago.

Thanks for choosing Just Answer . I'm Wolfgang here to help!!
Below is my first answer or request for more information. If you do not understand it, or you need more information from me, or need me to go in more detail. Do not rate yet, just reply. Put yourself in my shoes, I can not see, smell, hear, feel or touch your car, nor do I know any history on it. So take into consideration I am doing my best based on what you tell me. Also understand fixing cars often requires sophisticated tools, that you may not own. So even if you can not do what is outlined in my answer, that does not mean my answer is wrong deserving to be rated negative.

i do need a vin # ***** assist.

thanks

Customer: replied 1 year ago.
3vwse69m43m100068
Expert:  Wolfgang replied 1 year ago.

i need you to check if you have voltage on the red/black wire of the coolant pump when you start the car and the turn it off . the pump should run for 9 minutes after the key is turned off . you will need a volt meter to do this check please

thanks

Customer: replied 1 year ago.
Ok I will when I get home from work. I will tell you that the harness going to the pump got ripped off somehow and I got a new harness at junkyard but it has different color wires. I wasn't sure what way they went but I figured the pump would run in reverse. The pump just doesn't come on
Expert:  Wolfgang replied 1 year ago.

let me know

Customer: replied 1 year ago.
No power at either side of plug. Also my electric fans aren't working. I just replaced temp control switch.
Expert:  Wolfgang replied 1 year ago.

on top of the battery fuse box check all fuses especially the 3 green fuses!!

let me know

Customer: replied 1 year ago.
The green fuses are good
Expert:  Wolfgang replied 1 year ago.

you need to pull them and make sure that there is no black markings on the blade of the fuses then also check the 40 amp bolt in fuse make sure that is not blown. if ok then you need to make sure you have 12 volts on pin 1 and pin 3 of the 4 pin connector of the fan control module located under the drivers side frame rail under the battery.

Customer: replied 1 year ago.
Ok I will check for power. I replaced the FCM a couple months ago. But I never tested for power. It might b a day before I get back to u. I have work and basketball
Customer: replied 1 year ago.
Is that power with key on or off
Expert:  Wolfgang replied 1 year ago.

key on

Customer: replied 1 year ago.
I can't find a diagram to how the pins are numbered. Is it like reading a book. Left to right top to bottom
Expert:  Wolfgang replied 1 year ago.

on the connector there is #'s where the wires go in!!

Customer: replied 1 year ago.
The #1 and the 30a plugs were hot
Expert:  Wolfgang replied 1 year ago.

ok first need to check the wiring from the pump to the 14 pin connector near the battery. reistance checkfrom pin #1 of pump to pin 13 of the 14 pin connector and pin #2 to pin 7 let me know what you have in resistance

Customer: replied 1 year ago.
Ok. So those pins aren't numbered so how do I determine what pin is what
Expert:  Wolfgang replied 1 year ago.

all connectors has numbers where the terminal wire goes into the hardshell

Customer: replied 1 year ago.
Ok I see the PIN numbers. Do I test with key on or off
Expert:  Wolfgang replied 1 year ago.

when you do a resistance test key is always off

Customer: replied 1 year ago.
My meter just stays at 1 on both tests
Expert:  Wolfgang replied 1 year ago.

can you take a pic of meter and post here? i just want to make sure you are on the right setting when checking!!

Customer: replied 1 year ago.
I can't get a picture to upload. I have the black plug in common hole red plug in the resistance hole and I tried every setting in the ohms(200,2k,20k,200k,20m,2m)
Expert:  Wolfgang replied 1 year ago.

that means the wire has an open then need to stretch new wire from end to end and then recheck

Customer: replied 1 year ago.
Ok new wires from FCM to pump?
Expert:  Wolfgang replied 1 year ago.

now to make sure did you check the male side of the 14 pin connector or the female side of the 14 pin connector?

Customer: replied 1 year ago.
Female pins on the 14 pin male plug that plugs into FCM
Expert:  Wolfgang replied 1 year ago.

no there is a 14 pin connector if you take the air cleaner box out in the air box area then recheck the pins stated above!!

Customer: replied 1 year ago.
I've been sicker than a dog last 3 days. Went out today and took air box out. I see 3 runs of loomed wires that run under air box then go up into cowl area. Don't see any plugs. Am I in the right area
Expert:  Wolfgang replied 1 year ago.

when the air box is removed the 14 pin connector should be right there near the snorkel of the air cleaner that is still mounted .

Customer: replied 1 year ago.
Ok I found the plug and there is not a wire in the 13 pin. I suck at wiring that's why I'm here asking. What is the setting I should use on my meter and which end of the 14pin plug am I testing
Expert:  Wolfgang replied 1 year ago.

resistance ohms

Customer: replied 1 year ago.
Which side of the plug
Expert:  Wolfgang replied 1 year ago.

the side where the wires going to the engine

Customer: replied 1 year ago.
Ok. Also there is no wire in the #13 pin.
Customer: replied 1 year ago.
Pin #2 to #7 .05 set at 20m. 76.5 set on 200k. #7 is a heavy brown wire. No wire in the #13 position
Expert:  Wolfgang replied 1 year ago.

ok here is the diagram . you need to check the v51 wires

Customer: replied 1 year ago.
What kind of check and from where to where
Expert:  Wolfgang replied 1 year ago.

resistance check from the fan control module pin 13 to pin 1 of the water pump and then pin 2 of the water pump to pin 7 of the 14 pin connector at the air cleaner area.

Customer: replied 1 year ago.
There is nothing from #13 to #1 on water pump. There is continuity from #1 to #1 and #2 to #6 on the water pump plug to the FCM plug. On the #2 to #7 test it started with resistance then settled down to 0
Expert:  Wolfgang replied 1 year ago.

then 13 to 1 has an open that needs to be rectified first then recheck

Customer: replied 1 year ago.
I don't understand where 13 is supposed to be going. #1 and#6 are accounting for the two wires that are going to the pump plug
Expert:  Wolfgang replied 1 year ago.

forget 13 if 1 to 1 is good . how about 2 from pump to ground on the battery what is the resistance?

Customer: replied 1 year ago.
It's #6 in the FCM harness. I didn't check resistance I just did a continuity test. Do I test the ground in the plug or test it actually to the battery
Expert:  Wolfgang replied 1 year ago.

to the negative side of the battery

Customer: replied 1 year ago.
0.00 resistance from plug #2 on pump to neg battery cable
Expert:  Wolfgang replied 1 year ago.

ok that is good!! do you have voltage at pin 4 of the fan control module (14 pin connector)

Customer: replied 1 year ago.
power to #4. That is only one with key off that has power
Expert:  Wolfgang replied 1 year ago.

ok the next step is to unplug the radiator fan switch on the radiator drivers side and should be a triangular plug and jump 2 terminals the red wire and the red/white wire first and tell me if the fan speed is fast or slow and then jump terminals red and red/yellow and tell me the speed of the fans

thanks

Customer: replied 1 year ago.
I have done that and I got a hi and low. The high only worked with the key in the on position the low worked with key off
Expert:  Wolfgang replied 1 year ago.

ok if that is good then the fan control module's logic circuit for the pump is damaged internally and will need a new fcm.

Customer: replied 1 year ago.
I have already replaced the FCM and the temp sensor that was the fan plug I just tested. That is when I contacted u. So when is that pump supposed to run
Expert:  Wolfgang replied 1 year ago.

that pump on;y runs after the car is turned off for about 10 minutes at operating temperature. if cold it may not run depends on the temp of the engine

Customer: replied 1 year ago.
I guess I'll put it back together and try it. I don't know what else to check. I even took apart one of the FCM units cause I heard that the contacts stick but it looks great
Expert:  Wolfgang replied 1 year ago.

ok let me know!!

Customer: replied 1 year ago.
Is there a way to jumper the plug by the battery to see if power will make it to the pump
Expert:  Wolfgang replied 1 year ago.

remove the plug and run 2 wires to the pump

Customer: replied 1 year ago.
I've jumpered the pump I was just wondering if I could do it farther upstream to see if it is not working down the line. It worked when I straight jumpered it
Expert:  Wolfgang replied 1 year ago.

how about a scan test from the engine ecu

Customer: replied 1 year ago.
Like a vagcom?
Expert:  Wolfgang replied 1 year ago.

correct!

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