DIY PTC (Auxiliary) Heater Install

[Timpanogos Slim]

confirmed - the studs on the bus bar are M5. I used a nylock nut and a washer.

Also, if you're not averse to t-taps, blue ones seem to be perfect for this application. I understand the potential issues with t-taps, but they seemed least worst for this junction, considering it's right above my right foot.

Works great. I get a defogged windshield in just a couple minutes from stone cold. Full on 'i wanna take my coat off' heat in less than 15 minutes. Highly recommended for the cold weather set.

 

[Natalie]

fwiw if anyone else is tired of waiting 15 minutes for windows they can see through, there are at least three more out there for a song:

(yes, i searched for the *electric heater core)

I didn't see electric heater core as an option to search by. Currently looking on their site to try and find one for my 2007 GTI. I'm having heating issues and this might be a DIY to help make due with my situation rather than pulling the dash and my hair out. I'm a little nervous cutting in to the canbus wires. Did you by chance take pictures of your install or splicing into the comfort canbus?

 

[Natalie]

Also, if you're not averse to t-taps, blue ones seem to be perfect for this application. I understand the potential issues with t-taps, but they seemed least worst for this junction, considering it's right above my right foot.

What are the potential issues with t-taps in this type of use? Seems like a very easy solution to tap into the two wires. Needed.

I ordered mine from an 06 Jetta TDI with 50k miles for $85 instead of the ones for $40 which had anywhere from 140k to 220k miles on them. Slim is the hammer crimp you referred to necessary to crimp the lugs on or it just makes it a lot easier? I might just see what my local NAPA has or if they'll crimp it all for me if I buy the wire and lugs from them.

Also did you have to cut another hole through the firewall (same area as the gasket) or were you able to slide it near the other wires through that existing gasket opening?

 

[Natalie]

Ended up purchasing a hammer crimp tool to make sure the crimps would be solid. Received the heater core in the mail yesterday but when I opened it I noticed they had sent me the water core and not the auxiliary heater.

After a phone call and some images sent to them they should be getting the correct one sent my way. Still waiting on a few parts but also thankful that the -23F weather has passed for now.

 

[Timpanogos Slim]

wow sorry i never remembered to subscribe to this thread.

I didn't take pictures of the splice. You're gonna be on your back with your head on the brake pedal.

The thing with t-taps is that if you use the wrong size or the junction has to move a lot you can end up damaging or even severing the wire.

But the blue ones (I forget what size blue ones are) seem to fit perfect and it's not somewhere you're gonna spend a lot of time.

To be extra careful you could deposit some liquid electrical tape or RTV silicone on either side of the tap to help keep the metal fatigue down.

You really only need about 6 inches off of each wire, and when you unwrap the harness it's not hard to find the right wires. Pins 1 and 2 are clearly marked on the connector in the heater core.

A good solid crimp is necessary, and the hammer type crimp is stronger. Loose high current wires cause fires.

 

[Timpanogos Slim]

Also, car-part can be weird.

when i searched for 2006 jetta heater core originally, it gave me the electric vs. water option.

Today a friend is interested in the dumb version for a project, so i search for 2009 jetta, no option, no way to select tdi.

selected 2009 rabbit, it asks if i want electric or water. WHATEVER.

Regardless, you want one from a 2006-2007 for this job, afaik. My friend has a mk2 with a 20v swap and he wants the water core gone. he may have to rig up some kind of thermostatic control unit.

 

[Natalie]

Update**

Received another water heater core from the same place after sending them pictures and a diagram to pull it from the 2006 TDI. Unfortunately they just don't listen to what I have to say so they're back at it again trying to get the correct part while I have two heater cores laying around...

In the mean time I got the wires crimped and I have to say the tool works very well for that. No surprise, but I would also speak to it being a good investment for this project. Hopefully soon they'll figure out what part I want and I can start this install.

 

[Timpanogos Slim]

Wow, talk about shit luck

. :Sent by pneumatic tubes

 

[Natalie]

Had to call LKQ back again today to re-explain for a third time how to find the part and to not pull another water core. I know it can be a little confusing to explain but with pictures, a VW diagram and instructions they have managed to still be baffled by this. Hope to have a solid answer tomorrow before they ship it out. :mad0259:

 

[Natalie]

LKQ told me they couldn't find the part in any of their yards across the country. I'll be getting a refund and I still get to keep the two water heater cores they sent. Time to start calling other yards to see if they've got the electric version. Frustrating but at least i'm not out anything so far.

 

[Natalie]

Finally got around to installing my auxiliary heater this afternoon. Found a different auxiliary heater in Iowa. Total install took me about 6 hours to do by myself. I don't have the luxury of a heated garage but the garage still helped.

Tips for other attempting this:
I followed Timpanogos Slim and used t-taps 14-18 gauge from Radio Shack to tap into the canbus. The from what I could tell it looked like the wires on the canbus were 18 or 20 awg but the t-taps worked for me. The taps I had used the male butts to attach the repair wire to the t-taps (also got these at Radio Shack).

1 repair wire was perfect for this install. It comes with the pins installed on both ends of the single wire they provide (about a foot long). Cut that in half and you have a wire and pin for each of the pins for this install. The length was also more than enough for this install. The Canbus wires and the connection on the heater are ~4-5 inches away.

When on your back trying to figure out which wires you're tapping into the orange/green is very obvious but the orange/brown isn't as clear as there are a few other orange/brown combinations to choose from. What made it more obvious to me was once you unwrap the wires you'll noticed that the orange/green is braided with a set of orange/brown. I figured this had to be it and everything works for me. Once I figured that out it really wasn't as daunting as I thought it would be splicing those wires. Hope that helps to clear up any confusion.

Taking out the footwell vents was a necessity for me. It definitely gave me the extra clearance to get the heater in. I think you could get away with just loosening the connection enough without taking the 1 t-20 screw out so you would be able to just push the vent aside but I removed that. It also involved taking out the headlights switch and the plastic (Left hand knee) panel that it was sitting in to access that 1 t-20 screw.

I would also say that you don't need 4 feet for the negative connection or 6 feet for the positive terminal. 5 and a half feet would be more than enough for the positive and 2.5 would be good for the negative. I ended up finding space for the extra 4 awg wire but it isn't the easiest on a cold day to bend it into the areas you want it to go.

I ran into some issues with the fuse bending a bit because either end of metal on the fuse is very malleable. I was able to bend it back so no problems there.

On the negative terminal I ended up using my bench vise to bend the lug at at 45 degree angle. I also had to trim the plastic around the terminals on the heater core. It doesn't seem like any lugs but the ones you would order from the dealer would fit in that small area.

Added the coding to the canbus and test drove it for a few miles. It definitely works but I'll have to see what it does when I drive at higher speeds where you can get more output from the alternator. I did notice the warm air after about 2 minutes for me while it was 4F outside. Will be doing a log tomorrow to see how long it takes to warm up the interior compared to my logs without it. Now all I need are heated seats!

:smile:

 

[Natalie]

Anyone know the difference between 7D (auxiliary heating) and 18 (auxiliary heater) in the can gateway?

 

[Timpanogos Slim]

Yeah, one of them is a webasto coolant elbow heater that you don't have.

Iirc 7d is the one you want to enable. It will throw a code if you tell the gateway that you have something that isn't really there.

Wrt heat output my concern was w/ no garage it was taking 15 minutes or more before the windshield could defog.

More like 2 now.

I don't find that it blows hot air right away either.

. :Sent by pneumatic tubes

 

[Natalie]

I had 18 installed on the can gateway originally and then changed it to 7d and made the proper coding in the central electronics module. I then when into the module for the Auxiliary heating (7d) and did the output test. The voltage was 14-15v while idling and output in Watts was ~500 or so. Aux Heater said it was ON in the output test. It definitely seemed to come on with the output test but I wasn't sure this morning that it came on while driving.

I performed a log on my 35 minute commute this morning and one of the advanced measure values I was logging was PTC Heater (actual), it's an ON or OFF value. It was OFF the entire time according to this value. I'm not sure if this is accurate or if there is something else to tell me why the heater would not be working (if that is the case).

Below I've posted the original log from after I put in rigid insulation (prior to aux heater):

This is today's log:

I realize speeds are different but it seems to have taken a little longer to get the cabin temp up to 65 degrees with today's log. Today it look 12.7 minutes to reach 65F interior. Previous log (similar outside temp) was about 8-9 minutes to get 65F.

Yes a number of factors could be accountable for this but I'm just trying to see if there would be a noticeable climb in interior temp with the PTC installed and I don't seem to see that difference. Any thoughts on why it wouldn't come on? Temperature gauge was all the way on. Fan was on 2. I don't need to have the A/C switched on do I? I'm at a loss so far.

 

[Natalie]

Well after I scanned the auxiliary heater for codes I found these two. I don't think the heater has been working at all on it's own.

I can get the heater to come on through the output tests in 7D module itself though.

So it's recognized, current goes through the heater, and I feel heat come out of the vents. It seems to contradict both that is broken and that there is no signal to it. I also assume if I didn't have a signal or wasnt able to communicate with it that I would never have been able to add 7D Auxiliary Heating to my canbus coding.

No idea what to do with this? Anyone have ideas?