Author Topic: Running a cable from engine bay to passenger compartment. (Read 2124 times)

GBH · « **on:** July 22, 2022, 10:19:14 AM »

Having fitted parking sensors to the front bumper I now need to run the sensor cables through the engine bay and into the passenger cabin (to a control box). The problem is that I cannot see an easy route through the firewall without major dismantling.

It has been suggested that I drill a hole through the passenger foot-well, but on inspection it looks as if this is not as simple as it first appears due to plastic under trays and carpets that appear to be held in place by interior plastic panels and have some sort of plastic block stuck beneath the carpet in the foot well.

Has anyone done anything similar before and found a simple route through?

TIA

Lord Voltermore · « **Reply #1 on:** July 23, 2022, 07:40:46 AM »

I dont know this particular car. But you can often find somewhere where a large bundle of wires, bound into a loom, pass through a rubber grommet into the interior. If so feed a piece of stiff wire,or a flexible curtain wire through the same grommet and use this to pull the wire through. If you cant find a bundle of wires try poking the flexible curtain rod into various cavities ,as sometimes these lead right through, without it being obvious that they will. On a Yaris I was once able to feed a wire by going down the inside of a front wing and it then easily passed through, emerging near the front door hinges.

Try to avoid drilling a hole.You may drill into a double void or into something important and expensive. If you do drill a hole be sure to protect the edges from rust, and fit a rubber grommet to stop the wire chafing.. (Nice wensleydale Gromit

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GBH · « **Reply #2 on:** July 23, 2022, 04:43:56 PM »

Thank you My Lord, My concern was, as you rightly say, drilling into something the other side that may either lead to a blind cavity or destroying something important (and/or) expensive.

Have run many cables over the years but those vehicles had engine compartments with plenty of elbow room where you could hold a party with your mates (think MGB, Triumph Herald/Spitfire?GT6, Sunbeam Rapier) and you will appreciate my concern that I find it rather difficult to get my hands into a Jazz's engine compartment, let alone stick my head in for a dekko!

Have already run the cables into the engine bay, but after looking underneath expecting to see the underside of the engine, transmission etc. I was somewhat befuddled to only see under-tray as far as the eye could see, from front bumper to some way half way down towards the back bumper. O.K. so I exaggerate slightly, but basically I would like to do as little dismantling as possible due to age catching me up (had classic minis before they were considered classic) and the only flexible joints I have exists on my car.

Will have another look at the inside of a front wing but using a bright torch this time might help.

Thanks for the pointers.

(P.S. Have already been on to Wallace and ordered a box of Wensleydale).

GBH · « **Reply #3 on:** July 30, 2022, 05:50:34 PM »

Thought I should update the thread as I never like a story without an ending (good or bad).

My son helped me out this morning and drilled a hole in the driver's side fire wall, somewhere just above the steering column. We initially thought it was double-skinned but appears not to be in that area.

The reason for choosing that point was that it was probably more accessible than the passenger side. All now fitted (with grommet for the wiring) and working through an on/off switch located in the blank cover in the switch console by the right knee.

Was it worth it? Possibly not as the aftermarket system I used does not really have the fine adjustment I was hoping for, although I have yet to use it as I intended.

Lord Voltermore · « **Reply #4 on:** July 31, 2022, 07:51:14 AM »

Glad its sorted. A boring tale that augers well. (by which I mean a tale about boring a hole with an auger

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GBH · « **Reply #5 on:** July 31, 2022, 08:32:49 AM »

Had a practice this morning and it appears that the signal goes to a solid, single tone when I am one foot away. Cannot get it to adjust closer than this (was hoping for a couple of inches rather than feet) so need to practice for getting that little bit closer.

Does at least avoid me ramming the garage door.

Markogden · « **Reply #6 on:** July 31, 2022, 10:24:33 AM »

Might be a bit redundant for you now but help others, I needed to route a power lead through my bulkhead/firewall this weekend and managed to find one on the passenger side behind the glove box to the left. I think mine was already split open inside the car which made it easier to spot and route the cable. I had to remove the windscreen wiper assembly and shelf/plastics to get enough working space to cut back the tape on the gromit in the engine bay and get the cable through. Used the following yt video for the steps on removing the wiper assembly

Attached some pictures that show the location of the gromit.