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04 MGTF Sunstorm 135. VW Arteon RLine 2.0 TSi. Vauxhall Corsa 1.4 SE
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Discussion Starter · #1 ·
Hi all - as a part of my 04 seat refurb, I’m installing heated seat pads to both seats. The kit comes with switches and a relay. Electrics are not my thing so I’m hoping you can advise me which fuse (and fuse box) I should take power from, how I do this, and how I ensure it’s a live that only switches on with ignition (I know the cig lighter is permanent live). I was thinking of taking the earth by self tapping into bulkhead unless you think there’s a better way?
if anyone can translate the instruction photo below it would help immensely 😏
Many thanks in advance
Steve
Eyewear Font Slope Cable Wire
 

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2002 MG TF VE51FTF
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The "key to the door on line" obviously relates to celebrating your 21st on Facebook the other ones got me stumped.

I suspect your holding some pictures back? what's the relay like? there must be more info.

You really need to know what current they draw I suspect it might be pretty high, even if you wire it from the live side (before the fuse) of the fuse box with an in line fuse you need to know that the wire supplying the box can carry the extra load on top of it's normal load.

The earthing points are in this pic if it helps.
Land vehicle Car Automotive parking light Vehicle Automotive lighting
 

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04 MGTF Sunstorm 135. VW Arteon RLine 2.0 TSi. Vauxhall Corsa 1.4 SE
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228 Posts
Discussion Starter · #3 ·
The "key to the door on line" obviously relates to celebrating your 21st on Facebook the other ones got me stumped.

I suspect your holding some pictures back? what's the relay like? there must be more info.

You really need to know what current they draw I suspect it might be pretty high, even if you wire it from the live side (before the fuse) of the fuse box with an in line fuse you need to know that the wire supplying the box can carry the extra load on top of it's normal load.

The earthing points are in this pic if it helps.
View attachment 139285
😂
C0360 looks favourite. Presume it’s a bolt under the dash?

Here’s some additional info:-
Font Screenshot Number Parallel Document

Electrical wiring Cable Wire Auto part Dvi cable
 

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If I was wiring this up I would take the permanent live feed directly from the battery, if no fuse is built into the control box you will need to install an inline fuse, the fuse will need to be 6 AMPS or slightly higher.

The red wire I would tap into an ignition switched feed such as the switched line going to the rear of the radio. The yellow wire perhaps to the input of the rheostat on the dashboard.
 

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1995 MGF Mpi
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1,078 Posts
@RichinVancouver, who used to to have an F, installed day time running lights in his F and powered the DTRL module using a piggyback connector on fuse #15 in the main fuse box. Fuse #15 is for aircon, which his F didn't have.

When I installed a boot release in my F, I got power from one of the 3 spade connections that you can see on the main fuse box picture, to the left of the black fuse puller tool. I used an inline blade fuse holder similar to the piggyback fuse in the picture that my friend Rich used.
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There are a number of places in the fusebox to take the feed. Little known is that these 'spare' connectors like the 3 in the row (not used) in your picture can be used. Each are numbered on the fusebox casing.

So taking the three in Mowog73's picture:

No 3 - Ign switch (ign sw) (fuse 17)

No 4 - Do not use as linked to tail lights (fuse 7)

No 5 - Perm live (fuse 12)

All are connected via specific fuses in the fuse box numbered as above. The correct connectors are available (metal within a plastic sheath) if you want to achieve an OEM look,

So for your heated seats, use No 3 and No 5 (live) and earth take from the earth point to the right of the fuse box.
 

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04 MGTF Sunstorm 135. VW Arteon RLine 2.0 TSi. Vauxhall Corsa 1.4 SE
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228 Posts
Discussion Starter · #7 ·
If I was wiring this up I would take the permanent live feed directly from the battery, if no fuse is built into the control box you will need to install an inline fuse, the fuse will need to be 6 AMPS or slightly higher.

The red wire I would tap into an ignition switched feed such as the switched line going to the rear of the radio. The yellow wire perhaps to the input of the rheostat on the dashboard.
Thanks Chris. 🙏 Do you mean the heater rheostat?
 

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04 MGTF Sunstorm 135. VW Arteon RLine 2.0 TSi. Vauxhall Corsa 1.4 SE
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228 Posts
Discussion Starter · #8 ·
There are a number of places in the fusebox to take the feed. Little known is that these 'spare' connectors like the 3 in the row (not used) in your picture can be used. Each are numbered on the fusebox casing.

So taking the three in Mowog73's picture:

No 3 - Ign switch (ign sw) (fuse 17)

No 4 - Do not use as linked to tail lights (fuse 7)

No 5 - Perm live (fuse 12)

All are connected via specific fuses in the fuse box numbered as above. The correct connectors are available (metal within a plastic sheath) if you want to achieve an OEM look,

So for your heated seats, use No 3 and No 5 (live) and earth take from the earth point to the right of the fuse box.
Great stuff! Much appreciated all 👍
 

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04 MGTF Sunstorm 135. VW Arteon RLine 2.0 TSi. Vauxhall Corsa 1.4 SE
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Discussion Starter · #9 ·
Out of interest, I saw on here that another installer hid the switches inside the ash tray. I’m thinking of doing this too.
 

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04 MGTF Sunstorm 135. VW Arteon RLine 2.0 TSi. Vauxhall Corsa 1.4 SE
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228 Posts
Discussion Starter · #11 ·
There are a number of places in the fusebox to take the feed. Little known is that these 'spare' connectors like the 3 in the row (not used) in your picture can be used. Each are numbered on the fusebox casing.

So taking the three in Mowog73's picture:

No 3 - Ign switch (ign sw) (fuse 17)

No 4 - Do not use as linked to tail lights (fuse 7)

No 5 - Perm live (fuse 12)

All are connected via specific fuses in the fuse box numbered as above. The correct connectors are available (metal within a plastic sheath) if you want to achieve an OEM look,

So for your heated seats, use No 3 and No 5 (live) and earth take from the earth point to the right of the fuse box.
Hi Julian - thanks for your advice. Not too bothered about OEM look. Will these take a standard (6.3mm I think) spade connector with plastic sheath?
Cheers
 

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Starlight Silver MG TF 135
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Steve, the additional data you posted quotes 24 - 36 Watts PER PAD and total of 4 pads. Using the nominal 12 volt supply, that equates to 3 amps PER PAD (assuming the 36Watt quoted maximum). Multiply by 4 pads gives a total of 12 amps, so a 15amp fuse seems in order to me. Bear in mind that with the engine running, the system will see 13.5 Volts or thereabouts, and possibly that is where the 36Watts end of the power rating they quote comes from. If you have a multi-meter, checking the resistance of a pad or pair of pads might be a better way of checking how much current they will draw. as you probably know, I = V/R where I is current in Amps, R resistance and V (obviously!) voltage.

If you have no heated rear window, the easiest source of power and switchgear would be to use a standard HRW switch and relay. I understand that somewhere in the supply to that switch (or possibly to an "enable" line to the relay), a signal from the oil pressure switch ensures that the HRW ONLY works when the engine is running.

Given the fairly high current draw for your seat-heating pads, this seems a wise precaution for powering them. You certainly want to ensure that the pads are NOT left on when the ignition is off, otherwise a flat battery will be the result!

In your kit, The thin Orange wire and Thin red wire "key to the door ON line" are, I suspect intended to ensure that you do NOT end up with a flat battery, by providing a similar "enable" line function to the relay in that kit. This provides the same function as what Rover did for the HRW. This is pure guesswork, but seems logical to me.

If you do have a HRW, you may find the line into the back of that HRW switch which only comes live (or possibly earthed) when the engine is running.

As regards your kit, If I were in your shoes, I would start by connecting the thick red wire, via a 15amp fuse, to a 12V battery +ve. Thick black wire to neg terminal of same battery, check for any output, then try first connecting each of the thin wires to the neg terminal, then via a fuse to +ve, if still no output, try orange thin to neg and thin red via a 3map or similar fuse to +ve. That last combination seems most likely to enable the relay, but (yet again!!!) pure guesswork.

When you have what seems to be the magic combo. Try it again with the heating pads connected.

I am assuming that the actual switch they provide for switching on the pads plugs into the relay loom somewhere obvious, and you will need to cycle that switch each time you try a combination.

OUTPUTS AT FUSEBOX BELOW STEERING COLUMN
Mowogs picture is, I suspect of a 1995 F fusebox.

I think your car is an 04 TF, and therefore more likely to look more like my 02TF:
Computer hardware Machine Electronic device Font Circuit component


Sorry this only shows outputs No.s 4&5, near the LH edge of picture I took this to explain to a supplier that they had sent the wrong relay when I fitted the HRW circuit. At that time I probed these outputs, with ignition on and off and came to the following conclusions:

OUTPUTS (Unused as standard)
1. Live only when ignition ON
2. no output, but I DID NOT try running the engine, so worth you trying with engine on?

3. Live in ACC or Ignition ON positions
4. no O/P observed, but worth checking engine-on

5. Permanently LIVE +

6. (N.B. This terminal higher up, as I recall)no O/P observed, but worth checking engine on

I (and others who want warm seats) would be interested to know how you get on. Post the end result, when convenient.
 

· Registered
04 MGTF Sunstorm 135. VW Arteon RLine 2.0 TSi. Vauxhall Corsa 1.4 SE
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228 Posts
Discussion Starter · #13 ·
Steve, the additional data you posted quotes 24 - 36 Watts PER PAD and total of 4 pads. Using the nominal 12 volt supply, that equates to 3 amps PER PAD (assuming the 36Watt quoted maximum). Multiply by 4 pads gives a total of 12 amps, so a 15amp fuse seems in order to me. Bear in mind that with the engine running, the system will see 13.5 Volts or thereabouts, and possibly that is where the 36Watts end of the power rating they quote comes from. If you have a multi-meter, checking the resistance of a pad or pair of pads might be a better way of checking how much current they will draw. as you probably know, I = V/R where I is current in Amps, R resistance and V (obviously!) voltage.

If you have no heated rear window, the easiest source of power and switchgear would be to use a standard HRW switch and relay. I understand that somewhere in the supply to that switch (or possibly to an "enable" line to the relay), a signal from the oil pressure switch ensures that the HRW ONLY works when the engine is running.

Given the fairly high current draw for your seat-heating pads, this seems a wise precaution for powering them. You certainly want to ensure that the pads are NOT left on when the ignition is off, otherwise a flat battery will be the result!

In your kit, The thin Orange wire and Thin red wire "key to the door ON line" are, I suspect intended to ensure that you do NOT end up with a flat battery, by providing a similar "enable" line function to the relay in that kit. This provides the same function as what Rover did for the HRW. This is pure guesswork, but seems logical to me.

If you do have a HRW, you may find the line into the back of that HRW switch which only comes live (or possibly earthed) when the engine is running.

As regards your kit, If I were in your shoes, I would start by connecting the thick red wire, via a 15amp fuse, to a 12V battery +ve. Thick black wire to neg terminal of same battery, check for any output, then try first connecting each of the thin wires to the neg terminal, then via a fuse to +ve, if still no output, try orange thin to neg and thin red via a 3map or similar fuse to +ve. That last combination seems most likely to enable the relay, but (yet again!!!) pure guesswork.

When you have what seems to be the magic combo. Try it again with the heating pads connected.

I am assuming that the actual switch they provide for switching on the pads plugs into the relay loom somewhere obvious, and you will need to cycle that switch each time you try a combination.

OUTPUTS AT FUSEBOX BELOW STEERING COLUMN
Mowogs picture is, I suspect of a 1995 F fusebox.

I think your car is an 04 TF, and therefore more likely to look more like my 02TF:
View attachment 139291

Sorry this only shows outputs No.s 4&5, near the LH edge of picture I took this to explain to a supplier that they had sent the wrong relay when I fitted the HRW circuit. At that time I probed these outputs, with ignition on and off and came to the following conclusions:

OUTPUTS (Unused as standard)
1. Live only when ignition ON
2. no output, but I DID NOT try running the engine, so worth you trying with engine on?

3. Live in ACC or Ignition ON positions
4. no O/P observed, but worth checking engine-on

5. Permanently LIVE +

6. (N.B. This terminal higher up, as I recall)no O/P observed, but worth checking engine on

I (and others who want warm seats) would be interested to know how you get on. Post the end result, when convenient.
Will do, and thanks for the advice. I’m going to have to read it a couple more times to get to grips with content. I do have the HRW installed but that wiring was plug and play 😂
 
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