E90 wiring routing help

unicornsareus · 10-02-2023, 10:06 AM

Hello,

I have been looking at this forum for years to look up stuff for my e90, and I finally made an account because I could use some help.

I have a 2008 328xi that I am going to be putting in an oil pan heater on as I live in an area where it can be -30C for weeks. While I can park it inside my garage at home, I have to park it outside where I work.

I have yet to come across a DIY for something like this or pictures.

I have found a heater that I am positive will work, but I just need some help with where I should run the cord through if anyone has any tips or tricks. I would like the cord to come out at the rear bumper where I plan on installing a shore power port. I will be plugging in a battery trickle charger, and the oil pan heater.

Experience wise, I am a heavy duty mechanic who does work like this on heavy trucks, but not so much on cars.

On a side note, if anyone here has found a way to install a Coolant Webasto heater, I would *love* to know how. I have a bunch of spares sitting in my garage and I'll happily rig a spare separate battery on there. I'd much rather put a Webasto than an oil pan heater any day.

unicornsareus · 10-03-2023, 11:02 PM

So, while I never ended up getting many replies. I thought I'd post how I routed my wire from the front to back. If someone wants, I can make up a horrible rough DIY for how to do this.

I live in an area where it can be -30C for weeks. I want to be able to drive away sooner instead of waiting 10-15 minutes warming up to not damage anything. I had to boost my battery multiple times last winter (albeit that was because of a bad battery). iDataStart remote starter has also been a god-send I installed last year. There were not many places to mount the heater unfortunately, and very few sizes would have worked. The one I installed is a Philips Temro 125W 3in diameter one. $136 on sale at Greggs. Already had the stick on pad, just asks that you clean surfaces and apply silicone after installation.

The entire imgur album is available here:

The oil pan heater I installed:

(Yes, the oil pan gasket is leaking. I will get to it some day)

I had access to so some metal ducting tape, helped to get the harness a bit more rigid, and it's a little more heat resistant and last longer from the hot-cold cycles. I also had some split loom to protect it further.

I found the Positive Battery cable and routed my wire to it.
I purposely left the plug there, because I know one day I will attempt the oil pan gasket, and I don't want to have to cut wires there.

The Positive cable hides above the fuel tank, so I got creative.
Didn't really have somewhere to clip the wire onto this area, so I drilled some holes and double zip tied it.

I would highly advise against using these stick on zip tie holders, they suck.
My way is to clean the surface with brake cleaner/ether, then add a tiny drop of super glue, and hold it on for a good minute before letting go.

The tension on the wire cord itself will hold it well and not let it fall and get caught in anything.

EVAP Line?:

Some of those top zip ties were *not nice* to install. Especially when you're dumb and don't use safety glasses.

Some more pictures of the routing:

(Tied to the fuel filler neck)

Hockey taped. I deal with Peterbilts and Macks. Hockey tape generally works really well. I didn't want to spend more time zip tying, so for now some of it's just gonna hang a little bit.

Routed to above the bumper brace mount?

So for now I have just routed it into the Battery Box. Once the splitter arrives, I'll be installing it and I'll upload further pictures.

Old 80W battery warmer that has been sitting in my garage for over a decade:

Old Sprinter H8 gel cell battery I was able to get my hands on at work. Technically they wrote it off and replaced it because it froze, but the automotive tech was able to revive it, and revived it very well. I replaced my dying H6 AGM with it, programmed it. (This was all done months ago). Easy $300-500 saved.

I personally like to add a teeny bit of anti-seize compound on my hardware. Yes I understand some of it's plastic:

There will be more to come once I'm done installing the butt plug on the rear bumper.

StradaRedlands · 10-04-2023, 12:56 AM

Mandatory hockey tape... good on ya' and thanks for posting the DIY!

Serf27 · 10-05-2023, 03:29 AM

Did you add a fuse to the positive wire going from the batt to the heater?

ptpending · 10-05-2023, 04:42 PM

not sure why you ran so long cable thru whole car
scandinavian people simply route out connector thru front kidney or bamper grills
because their outdoor parkings places have 220V sockets with timers
they connect such heater to 220V thru intermediate connector and set timer for the morning slot
also the BMW cars have genuine webasto retrofit kits and intergrations to the car heater
but US engine firmware is not happy that engine was sleeping for 8 or more hours and for some reason(webasto) became hot

)) so it is usually requires to reflash US DME with EU firmware

unicornsareus · 10-28-2023, 01:09 PM

Hello hello everyone! It's a late reply but I wanted to get all my data before I posted again.

Here is the final result! It doesn't warm up as much as I would like it to, but anything is better than nothing.

2" hole I drilled:

All taped up to the extension cords! - I didn't take all the pictures but they are neatly tucked away underneath with lots more zip ties.

Cord heading into the battery box for warmer - all grommeted up

And finally - the data!

I have a smart - timer that I experimented with time for. I find 3 hours prior to driving is good enough for now as the temperature doesn't change much after that. The weather has not been colder than -10 so I'll be experimenting further.

In general, it heats up the oil roughly 15 degrees Celsius compared to Ambient Temperature. I am pleased to also see that the coolant temperature is also affected from the ambient heat from the heater.

In the future I will be installing another extension cord for a 0.75A trickle charger. I'll be making the charger easily removable as I use it for other things on occasion.

Quote:

Originally Posted by Serf27

Did you add a fuse to the positive wire going from the batt to the heater?

I'm not sure what you mean - the battery warmer is a household plug - it is not being warmed by that battery itself.

Quote:

Originally Posted by ptpending

not sure why you ran so long cable thru whole car
scandinavian people simply route out connector thru front kidney or bamper grills
because their outdoor parkings places have 220V sockets with timers
they connect such heater to 220V thru intermediate connector and set timer for the morning slot
also the BMW cars have genuine webasto retrofit kits and intergrations to the car heater
but US engine firmware is not happy that engine was sleeping for 8 or more hours and for some reason(webasto) became hot

)) so it is usually requires to reflash US DME with EU firmware

The reason I installed it at the back is I prefer to reverse park. The plug socket I also installed is slightly lubricated with di-electric grease in case I forget to pull out my cord and drive away.

As for Webasto retrofit kits, I would LOVE to install one - but the information available is so limited. I do this for a living on trucks, but I can find documentation on trucks - not so much on BMWs. I don't want to randomly hook up a Webasto to some random lines. I don't even care about the firmware as I own a few spare coolant Webastos.

I do have a smart plug that I'm experimenting on timing and weather to find the sweet spots between energy efficiency and waste.

10-02-2023, 10:06 AM	#1
unicornsareus New Member 17 Rep 10 Posts Drives: 2008 328xi sedan, 2008 X3 Join Date: Oct 2023 Location: Canadia iTrader: (0)	E90 wiring routing help - front to rear Hello, I have been looking at this forum for years to look up stuff for my e90, and I finally made an account because I could use some help. I have a 2008 328xi that I am going to be putting in an oil pan heater on as I live in an area where it can be -30C for weeks. While I can park it inside my garage at home, I have to park it outside where I work. I have yet to come across a DIY for something like this or pictures. I have found a heater that I am positive will work, but I just need some help with where I should run the cord through if anyone has any tips or tricks. I would like the cord to come out at the rear bumper where I plan on installing a shore power port. I will be plugging in a battery trickle charger, and the oil pan heater. Experience wise, I am a heavy duty mechanic who does work like this on heavy trucks, but not so much on cars. On a side note, if anyone here has found a way to install a Coolant Webasto heater, I would love to know how. I have a bunch of spares sitting in my garage and I'll happily rig a spare separate battery on there. I'd much rather put a Webasto than an oil pan heater any day.
	Appreciate 1 StradaRedlands5962.50 Tweet Quote

10-03-2023, 11:02 PM	#2
unicornsareus New Member 17 Rep 10 Posts Drives: 2008 328xi sedan, 2008 X3 Join Date: Oct 2023 Location: Canadia iTrader: (0)	So, while I never ended up getting many replies. I thought I'd post how I routed my wire from the front to back. If someone wants, I can make up a horrible rough DIY for how to do this. I live in an area where it can be -30C for weeks. I want to be able to drive away sooner instead of waiting 10-15 minutes warming up to not damage anything. I had to boost my battery multiple times last winter (albeit that was because of a bad battery). iDataStart remote starter has also been a god-send I installed last year. There were not many places to mount the heater unfortunately, and very few sizes would have worked. The one I installed is a Philips Temro 125W 3in diameter one. $136 on sale at Greggs. Already had the stick on pad, just asks that you clean surfaces and apply silicone after installation. The entire imgur album is available here: View post on imgur.com The oil pan heater I installed: View post on imgur.com View post on imgur.com (Yes, the oil pan gasket is leaking. I will get to it some day) I had access to so some metal ducting tape, helped to get the harness a bit more rigid, and it's a little more heat resistant and last longer from the hot-cold cycles. I also had some split loom to protect it further. View post on imgur.com View post on imgur.com I found the Positive Battery cable and routed my wire to it. I purposely left the plug there, because I know one day I will attempt the oil pan gasket, and I don't want to have to cut wires there. View post on imgur.com View post on imgur.com The Positive cable hides above the fuel tank, so I got creative. Didn't really have somewhere to clip the wire onto this area, so I drilled some holes and double zip tied it. View post on imgur.com I would highly advise against using these stick on zip tie holders, they suck. My way is to clean the surface with brake cleaner/ether, then add a tiny drop of super glue, and hold it on for a good minute before letting go. The tension on the wire cord itself will hold it well and not let it fall and get caught in anything. View post on imgur.com View post on imgur.com EVAP Line?: View post on imgur.com Some of those top zip ties were not nice to install. Especially when you're dumb and don't use safety glasses. View post on imgur.com Some more pictures of the routing: View post on imgur.com View post on imgur.com (Tied to the fuel filler neck) Hockey taped. I deal with Peterbilts and Macks. Hockey tape generally works really well. I didn't want to spend more time zip tying, so for now some of it's just gonna hang a little bit. View post on imgur.com View post on imgur.com Routed to above the bumper brace mount? View post on imgur.com View post on imgur.com View post on imgur.com So for now I have just routed it into the Battery Box. Once the splitter arrives, I'll be installing it and I'll upload further pictures. Old 80W battery warmer that has been sitting in my garage for over a decade: View post on imgur.com Old Sprinter H8 gel cell battery I was able to get my hands on at work. Technically they wrote it off and replaced it because it froze, but the automotive tech was able to revive it, and revived it very well. I replaced my dying H6 AGM with it, programmed it. (This was all done months ago). Easy $300-500 saved. View post on imgur.com I personally like to add a teeny bit of anti-seize compound on my hardware. Yes I understand some of it's plastic: View post on imgur.com There will be more to come once I'm done installing the butt plug on the rear bumper. Last edited by unicornsareus; 10-03-2023 at 11:15 PM..
	Appreciate 1 StradaRedlands5962.50 Quote

10-04-2023, 12:56 AM	#3
StradaRedlands Brigadier General 5963 Rep 3,585 Posts Drives: 2006 BMW 330i MT Join Date: Dec 2021 Location: SoCal iTrader: (2) Garage List 2006 BMW 330i [8.25] 2009 BMW 328i Touri ... [8.00] 2013 BMW X5 35i [7.80] 2011 BMW 528i [8.70] 2006 Mazda3 [5.50]	Mandatory hockey tape... good on ya' and thanks for posting the DIY!
	Appreciate 0 Quote

10-05-2023, 03:29 AM	#4
Serf27 Brigadier General 2879 Rep 4,332 Posts Drives: 335i Join Date: Apr 2018 Location: Sitting in a BMW. iTrader: (-1)	Did you add a fuse to the positive wire going from the batt to the heater?
	Appreciate 0 Quote

10-05-2023, 04:42 PM	#5
ptpending Colonel 518 Rep 2,894 Posts Drives: e81 Join Date: Dec 2013 Location: Poland iTrader: (1)	not sure why you ran so long cable thru whole car scandinavian people simply route out connector thru front kidney or bamper grills because their outdoor parkings places have 220V sockets with timers they connect such heater to 220V thru intermediate connector and set timer for the morning slot also the BMW cars have genuine webasto retrofit kits and intergrations to the car heater but US engine firmware is not happy that engine was sleeping for 8 or more hours and for some reason(webasto) became hot )) so it is usually requires to reflash US DME with EU firmware __________________ E81 2007 130i 6cylinder Montego blue Retrofits: Harman Kardon, High-beam assistant, Removable tow hitch. Auto-dim folding exterior mirrors. Lumbar support. Perfomance Brakes.
	Appreciate 0 Quote