Seat Heater Installation - VW Golf 4

Hello everyone,

I've read some threads in the different forums and I'm stuck.
I have an aftermarket Waeco seat heater and I want to combine it with the original VW switches. Everywhere it's said that it's possible, but it seems like no one has actually done it, or at least documented it in a way that I can understand.
I've also seen a parts list on a forum before, but I don't understand it either.
Can someone help me, because I really don't want to install these WAECO switches.
I would be grateful for any information you can provide, such as switch assignments, etc.

Thank you.
magixxx


Okay: Golf IV TDI, 66 kW, ComfortLine, manufactured in March 1998.

It's not that simple.

The original seat heater is continuously adjustable. A temperature sensor is integrated into the seat cushion, which controls the heating. By adjusting the potentiometer, you set a desired temperature, and a simple two-point controller then attempts to maintain a comfortable temperature, with varying degrees of success.

There are two versions: in one, all the components are integrated into a single unit, meaning the adjustment potentiometer, relay, and 'control' are all housed in a single box (like in a Golf).
or the potentiometer and relay are separate (Octavia).

You can now either try to find a suitable temperature sensor and retrofit it into the seat, and then use the original controller.

Alternatively, you could modify an original controller so that you use the potentiometer as a control for a (self-made) PWM circuit, and use that to activate the seat heater. It's recommended to use the original relay as a contactor for the load. While the original controllers have an on/off switch, it can only handle a few milliamperes.

CU Gremlin.

Hi,

Search for "seat heating" in this forum. You'll find a longer thread that I started, and in the course of that thread, you may also find details related to your problem.

Best regards,

Jan.

Hello Jan,

I've already studied your instructions, and I think they're perfect for removing the seats and using Waeco switches or similar ones. I would have preferred to use VW switches, though.
I believe that the VW switches already include the relay, but I'm not entirely sure.

Here are also Gremlin's comments:
There are two versions: in one, the entire assembly is integrated into a single unit, meaning the potentiometer and relay, along with the 'control' circuitry, are all housed in a single box (like in a Golf).
or the potentiometer and relay are separated (Octavia).

This was posted on another forum, but I don't quite understand the circuit.



The Waeco seat heater can be easily combined with the original switches. I've done it myself.
The temperature controller needs to be removed from the heating element, disconnected, and bypassed using a crimp connector. An NTC thermistor (5kOhm) that is adjusted to 8kOhm using a potentiometer is placed in its place. The NTC and potentiometer combination is connected to ground and to the original switch.

Cover for the seat heater switch, part number 8D0 937 731 (should fit).

Pin 1: Lighting.
Pin2: Heating element.
Pin 3: NTC thermistor, 8 kOhms.
Pin 4: Constant positive voltage.
Pin 5: Ignition positive.
Pin 6: Ground.






It only works to a limited extent. The seat heating will not get any warmer from approximately level 3, and the temperature will be very uneven. However, it's not a problem to remove the controller. The mats consist of two layers that are not glued together in the area of the controller. You can simply pull it out from underneath, cut it off, and bridge it with a crimp connector (805565-77; €5.75).

By the way, the Waeco controller doesn't regulate the temperature very well. There are noticeable temperature fluctuations.

I used the following parts:
2x NTC thermistors; 5kΩ at 25°C; part number 467243-77; €1.64 each.
2x Potentiometer; 5kOhm; 430854-77; €0.38 each.
some electrical tape or heat shrink tubing.
Possibly two multi-socket connectors and sockets with 4 poles, for installation under the seat.
2x connector; 846341-77; €0.40.
2x socket; 846376-77; €0.40.
6 x Flat pins; 845264-77; €0.10 each.
6 x Flat pin connector housing; 845299-77; €0.10 each.

2x Sitzheizungsschalter v. Audi.
2x the appropriate connectors.
14 individual connectors for the plugs (12) and 2 original fuse holders.

3 cables, 1.5mm², for positive connection (red), ignition positive (blue), and ground (brown).
2x 0.75mm² cables: yellow for NTC sensors, purple for instrument lighting.

Wrap a lot of electrical tape around the finished wiring harness (to prevent rattling).

I completely threw away the wiring harness from Waeco.

The heating elements are connected in series. Therefore, they operate at 6V, or, to be very, very precise, at 6.9V.



Perhaps you might have some ideas about this. Is this also the labeling used for the VW switch?

Thank you.
Stefan.

Hi,

Quote:

I've also studied your instructions, and I think they're perfect for removing the seats and using Waeco switches or similar ones from Conrad.

I didn't mean my instructions, but the thread that came before it (it's probably linked in the instructions, otherwise just search for it). The topic of the original switches came up in that thread as well...

Best regards,

Jan.

Hello,

You're right - I've looked at it more closely. There was also a schematic diagram there.
I think I'll just recreate it in a small 'test environment' using a PC power supply before I install it.

How does the side airbag work? I read something about an adapter, but I think if the battery is disconnected when I remove the seat, nothing should happen. Then, you can isolate the connector on the seat so that no voltage is transmitted.

Stefan.

Hi,

Side airbags could be a real problem – I suspect (I haven't looked into this closely before) that you won't be able to remove the cover without running into serious issues with the side airbag.

You should really try to get a definitive answer there, because that could easily derail your entire project.

Best regards,

Jan.

Hello Jan,

'This weekend, I took the car apart and installed the heated seats. Everything works perfectly, including with the original switches!'
I only used the 5k Ohm thermistor.

Best regards,
Stefan.

Hello Stefan,

That sounds really good. I've also been thinking for a while about whether I should install heated seats. However, what's always held me back is that I wouldn't have the original switches.

Could you please describe in more detail how the heating is working now? Are you experiencing the same problem where the heating doesn't get any warmer above level 3, and the temperature is very uneven? Have you replaced the Waeco controller?

Could you please describe in more detail how you implemented the circuit (specifically, which components, etc., you ultimately used)?

Oh yes, do the sports seats also have the side airbags? Are there really difficulties if you don't have the adapter from the workshop? According to Jan's description, you don't even have to remove the cover of the backrest, you just have to slide the heating element underneath it.

Best regards,
Marco.

Hello,

I've already replaced or completely installed seat heaters in two Volkswagen Golfs.

When installing the car seat for the first time, make sure to orient it with the airbag facing upwards.
I got stuck for the second time and only pushed the rear seats back out of their guides so I could tilt the part inside the vehicle. The rear center console should also be removed.
The airbag connector remained plugged in. The helper is now helpful! Jan6K has described the remaining steps well. The foam padding can be removed with the cover from the tub, allowing the work to continue outside the vehicle.

The seat cushion covers can be flipped upwards after the closure at the bottom has been opened and the two tensioning wires at the front bottom have been detached. During the flipping process, one or two crossbars need to be detached. Eventually, a gray plastic cover will appear – this is the airbag.

By the way, sliding the mats out from underneath didn't work for me, because there are too many wires in the way.

Best regards.

Helmut.

@RogerR

Hello,

I only have the hot air rework station from Conrad.
2x NTC thermistors; 5kΩ at 25°C; Conrad part number 467243-77; €1.64 each.

I cut the cable to the desired length and soldered wires to the ends on both sides. Then, I covered the whole thing with a heat-shrink tube to make it less susceptible to damage.
'Then I disconnected the battery and followed a guide I found online. I removed the seat cushion according to the instructions and disassembled it. I completely removed the upholstery and glued the seat pads in place, trying to minimize creases (although it's not entirely avoidable). I then glued the NTC temperature sensor to the back of the heating pad and routed the wires to the back. After that, I completely wired the seat, as the original Waeco seat heating pads had cables that were too short. I then attached a pluggable terminal block from Conrad to the bottom of the seat. I only connected the 45-watt heating level (i.e., the positive wire of the heating pad, the positive wire of the NTC sensor, and the ground wire) to the plug. Consequently, you need a plug with 3 connections per seat. Before connecting, the built-in temperature protection must be removed from the heating pads (see the previous post).'
Then I connected everything according to the wiring diagram in my previous post and used the pin assignments.
I completely removed the Waeco control unit with its switches, etc., because the cable cross-section was too thin for my needs.


Perhaps a few more details about the costs:
Conrad order with.

15 meters of red cable, 1.5mm diameter.
15 meters of black cable, 1.5mm diameter.
15 meters of white cable, 0.75mm diameter (for the sensor).
10 meters of purple cable, 0.75 gauge, for lighting power.
15 Flachstecker 6,3mm (zum Anschluss der orig. Switch.
2 * Thermistor
Insulating tape.

Approximately 15 euros.
Heizmatten Waeco bei eb** ca. 61 Euro incl. Shipping.
2 x Original seat heater switch - €26 each.

= 128 Euros
To be fair, I have to admit that I got the heated seat switch replacements from an online junkyard for a ridiculously low price (12 euros for both).

So, I ended up paying about 90 euros.

Regarding the function:

Level 0 = off.
Level 1 = Heating is barely noticeable / hardly noticeable.
Level 2 = very pleasant.
Level 3 = still pleasant, but not too warm for anyone.
Level 4 and 5 - too hot for me!!!

Compared to the original seat heater (which my brother has in his Golf IV), there's hardly any difference noticeable - the original might get warm a little faster and has a slightly larger seat surface, but I think you can live with that considering the price!

Here are a few more tips:
- Consider performing tests with 6.8 k Ohm and 10 k Ohm NTC resistors.
- Therefore, it's best to order them at the same time when placing your order.
- Be careful when removing the seat adjustment buttons - I broke one.
- Requires significant installation effort - allow 1-2 days - during this time, the car cannot be moved, as the battery must be disconnected until the seats are installed. (Otherwise, you need this adapter, which is not provided by the workshop).
- Use a lot of electrical tape to assemble the cable harnesses and insulate the connections.
- If the seat has already been used extensively, the driver's seat cushion may be worn out. - So, if you're already disassembling the seat, it's a good idea to install a new cushion right away, or swap it with the passenger seat.

Conclusion:
It was quite a hassle, but I'm totally happy with the heating system now - it's simply brilliant. If you have any questions, just let me know.


Best regards,
Stefan.


PS:
If you would like to receive the instructions as a PDF, simply send me a short email to [email protected].

Hi,

"Regarding the topic of 'warming up quickly':"

I'm experiencing the same problem in the 45W heating mode (since I can only control it in binary, 22/45). It takes a bit too long for it to get warm. Therefore, I'm considering modifying the system so that it either has a third setting (45+22), or that I use a timer to run both heating circuits in parallel for a few minutes when starting the heating process.

However, caution should be exercised regarding the current draw, as it could reach 11...12 amperes when both seats are heated.

Best regards,

Jan.