MCI DL3 sending new wires up the wiring chase

[plyonsMC9]

Good evening bus folks!

I would like to send new wires up the wiring chase.  Currently our DL3 could use some more wires running between the engine compartment and the front dash.  My temp gauge has gone wonky (not accurate) vs the mechanical, and not by a small amount.  When I run a test wire outside the bus between the temp sensor and the gauge, that particular irregularity is mostly eliminated.  I did try to pick some unused leads in the rear junction box that ran to the front J box, but that was a fail.  Irregular performance on those.  And I'd like to hook up a couple more dash gauges which currently don't have leads.

So, I'm thinking of running either a 4 or 7 wire 14 gauge 'trailer bundle' from the rear to the front panel.  Hopefully up the wiring chase. 

Do I have any chance of succeeding with this?  The rear J box is pretty tight, and I don't know what I'm about to encounter if I move forward.

Are there suggestions on how to best succeed w/ this adventure? 

Thank you!, Phil

[buswarrior]

The hvac refrigerant pipes have been known to be used as wire chases, if the ac has been removed.

That'll get you part way in a DL.

The old advice has always been to pull more wires than current plans require, there's always something else in the future that another wire would facilitate. Finding the spares unsuitable raises this to required vs optional, me thinks?

Happy coaching!
Buswarrior

[chessie4905]

if like gmc, pull all the chase panels. you may have to use a hole saw through a bulkhead or two if all holes are full. line with a grommet. mine had phillips and was a challenge removing panel above water and waste tanks as little clearance. replaced screws with socket head equivalent. and as above, double the number of wires or a little more.

[Jim Blackwood]

Where is this wire chase of which you speak? Are we talking about the big return air duct for the HVAC by any chance? That seems like it'd be a Big Job. I used the HVAC distribution ducts inside to carry my extra wires, 'course if you don't have those...

Jim

[epretot]

Not sure if this is helpful. But it might be.

Perhaps you can use the chase to the right. If you look closely, you can see the plastic shroud that comes from the ac/blower compartment.

This channel is open all the way to the driver seat behind the driver seat.

[epretot]

Here is the other end.

[chessie4905]

gmc's is top of baggage compartment center. runs from front to back. mci's may be different.

[plyonsMC9]

Thank you kind bus folk!

Re: number of wires - I was going to go w/ trailer 14 gauge - 4-wire ribbon.  But now thinking 7 wire / round as it would be more resistant to nicks & cuts which may happen during the process.  Though more difficult to fit and maneuver. As long as I'm going through this much work.  100' spool.  7 wires would get me more than the current plans require. 

This coach was never an OTR bus.  So I don't have the OTR a/c or heat, and no side a/c ducts. And I was indeed thinking of the center a/c return duct / chase.  I can see parts of that chase when in the various bays. 

I'll be scouting around per the suggestions below.

Ceiling chase maybe a possibility? 

Thank you all!! Reading & reading your ideas.

Kind Regards, Phil

[Van]

I did this on our H3 and did two 14/7 runs. First the wire; https://m.delcity.net/store/14:7-Trailer-Cable/p_820591.h_820616
Then installed (waterproof) terminal blocks  1 in the engine compartment, 1 in the front electrical compartment. Ran along the frame rails and then thru all the DS bays via 3/4" holes drilled w/grommets and P clamped to the bay ceiling. Easy peezy and no getting under the coach needed. Good luck!

[chessie4905]

or you can install 1" conduit front to back. pull a few or several through.

[windtrader]

Seems like a separate long pipe would be best to run front to rear. Easy to mount, easy to run wire, easy to terminate where you want on each end. Seems like you could even run lengthwise on the roof. Not seen, low profile, easy access on each end where you terminate. For that matter you could have a junction along the way to drop wires where you want. Of course, you need to gain access from inside that might cause some issues but maybe drop inside a cabinet or closet.

[plyonsMC9]

This is interesting, and so I'm clear, we're talking about a 1" conduit possibly fastened to the frame, vs taking cable through the central duct and / or bays?  I'm going to climb back under the bus to take a look.  After spending so much time under there messing w/ the air lines you'd think I'd have it all memorized.   

Thank you all! 
> Phil

[chessie4905]

that would also give you the easy option to add more circuits in the future. consider the grey pvc conduit. metal could cause some unknown future problem via corossion or shorting against a rubbed wire.

[Jim Blackwood]

Conduit is a good option, the issues include routing past the wheelwells and through the HVAC bay or fuel and battery bay. PVC is a good choice and easy to work with, and it's easy to add junction boxes at regular intervals which also can make pulling wires easier if more time consuming. There is a box with a removable sealed cover that would work well. I'd suggest going a bit larger than 1" though as it is far easier to pull wires through a larger conduit especially after some wires are already in place. Biggest you have room for would be the easiest to work with later. Not a bad idea to pull a heavy cord through so you can use it later to pull additional wires if needed. Something slippery and strong. I used 2" to cross the electrical bay for my 110v circuits and by the time I was done pulling wires wished I'd used the next size larger. If you pull several wires they can get twisted and wound around each other and that adds a lot of resistance to pulling. A lubricant is available but I've never used it. You can bend PVC conduit by heating it. A heat gun works well and you may be able to use hot water. Be careful of nicking your insulation as it goes in, having one person to pull and another to guide is the best.

Jim

[dtcerrato]

Our conduit runs past the back axle running the underside of the top wheel well contoured with the curve clamped to the wheel well "ceiling". In 43 years we have multiple runs on both DS & PS of bus and never utilized the pristine condition of the center full length raceway.