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Topic: Brake lights & Cruise Control on Freightliner Chassis

Posted By: FritoBandito on 03/19/09 10:26am

Have you ever experienced the lack of brake/stop lights or had your Cruise Control fail to engage or intermitently disengage?

Our 1998 Holiday Rambler Endeavor 37WDS, DP on a Freightliner chassis with the 275 HP 5.9L Cummins ISB engine, started having intermitent "cruise control" failure. Finally it quit working all together. Last fall on our way from WI to TX, the cruise control would not engage. I've been "chasing" the problem, via the wiring schematic, fuses, cruise control button on the turn signal lever, etc. ever since.

The other day a fellow from British Columbia pulled into our RV park with the identical model motor home. We talked about various subjects. Floor plan, big kitchen, improvements, etc. Eventually, we got around to "problems". He had experienced a brake light and cruise control failure. A mechanic finally located the problem.

A module that Freightliner calls a "BACK-UP LIGHT SWITCH" Part No. TDA RBE 13250. The module is 1-3/4" in diameter ... about 2" (overall) in length and has a "screw-in" 3/8" nipple with an "air inlet" and two electrical posts for wires with ring-connector eyelets. It operates off of air pressure and is mounted under the driver's side floor board. Apparently when the brake pedal is depressed, some of the air is also diverted to this module that closes a switch and sends 12-volts to the brake/stop lights AND disconnects the cruise control.

My original module had one electrical post that was loose in the "body" as well as the nut holding one of the ring-connector wires had become loose and the ring-connector was kinda "hanging" loose --- hence (what I hope caused) the intermitent cruise control.

I have yet to install the module, but Freightliner Corpus Christi told me that they have seen this problem before on "tractors" that they service.

I'll post again, after the module is installed and we get a chance to "hit the road". Keep your fingers crossed!

But in the meantime, has anyone else observed this malfunction?

Posted By: jtfcons on 03/19/09 10:43am

I think what you are refering to is simply a brake light switch...I replaced this switch a couple of years ago because cruise control would not engage at times and I noticed when parked in a RV park that my brake lights were on. Location of the switch is as you describe, below the floor and near the brake treadle area. To my knowledge this switch has nothing to do with the back-up lights.

John & Sharon, 2 Daughters, 2 Sons-in-law, 5 GK, 1GGK
Rat Terriers (Twiggy, Annie)
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325 Cummins C8.3Mech., MD3060, EBw/Coast.Sw.,
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Posted By: wa8yxm on 03/19/09 02:50pm

If cruise control fails to engage, ABS works, and brake lights do not work

Blown fuse Stop/Turn signals

If Cruise control fails to engage, ABS alarms when you start vehicle and brake lights seem stuck on

Brake Light switch failed shorted (ON)

The brake light switch is common to all 3 systems (ABS, CC and of course the lights it's named for) ABS looks for 12 volts on the lamp side of the switch

CC looks for 12 volts ACROSS the switch

So a blown brake fuse won't bother ABS but WILL the Cruise control, it will also prevent the brake lights from working

By the same token a shorted switch WILL bother ABS, and Cruise control and will light the lamps

Now.. BOB's (Burned out bulbs) they can take out the cruise control as well (in which case the lamps will not (can not) light) as can a bad ground on the lamps. but I do not know the effect on the ABS system.

Home is where I park it.
Kenwood TS-2000 housed in a 2005 Damon Intruder 377

Posted By: FritoBandito on 03/21/09 10:53am

Your statement ..."I think what you are refering to is simply a brake light switch ..." is what Freightliner (mistakenly) called the BACK-UP SWITCH on their invoice. Not me.
I believe you identified the correct part name and you're using the correct term.

WA8YXM ...
The 1998 Holiday Rambler Endeavor 37WDS does NOT have ABS. So my conclusion is that the loose wire attached to the BRAKE LIGHT SWITCH, made the brake lights fail ... or at best fail intermitently. I had no way of knowing, because the coach was moving down the highway at 62 MPH.

But if one of the wires to the brake light switch was loose and the brake lights failed to illuminate, that probably "kicked off" the cruise control, also.

Today the new Brake Light Switch gets installed and the lights get checked. The cruise control will have to wait until we hit the road, again.

Posted By: wa8yxm on 03/21/09 02:33pm

Yup, I re-read the earlier posts and I agree it is the brake Light Switch that failed in this case

NOTE: in my first post I suggested brake light switch as ONE of the suspects

The RE-Read says it is the ONLY suspect

Very clearly the brake light switch

My rig is a gasser.. It has ABS and it had a bad Brake Light Switch Same failure

Posted By: FritoBandito on 03/22/09 11:09am

We replaced the brake light switch yesterday.

As suspected, when we disconnected the two wires and unscrewed the module from the air manifold, ... one of the posts was damaged. The "bakalite" portion that holds the brass stud in place, was broken. Maybe a stone came off the road and "nailed" the post.
What are the chances of THAT happening?
If "Murphy's Law" exists ... and I'm a firm believer that it does ... about 99%, eh?

I'm going to use my Dremel and "open up" the module to see what the "guts" look like. I think the internal "switch" which sends current to the 3 brake lights is a simple, spring-loaded/normally "open" switch that "closes" when the brake pedal is depressed and air from system pushes on a diaphram. We'll see.

The old switch seems "heavy for its size".

Posted By: Jim@HiTek on 12/14/09 09:38am

Tagging this post since I have the same problem...

And wonder what the 'guts' of the switch looked like. FritoBandito? Did it look repairable? Or is it a 'needs replacing' item?

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Posted By: motodad75 on 03/04/10 11:38pm

Hello, I have a 1996 Holiday Rambler Endeavor 37WDS. My cruise control does not work at all. I will check the brake light switch tomorrow. Is the cruise control system fused ? It seams not to be getting power. I have a long trip planned soon and would really like to get it fixed.


Posted By: Jim@HiTek on 03/05/10 08:19am

I've learned since this posting of mine that there is another possible cause of the complaint 'Cruise control not working', there is a vacuum pump somewhere that operates both the dash heat and vent controls and the cruise control. Since I have both problems, I'm trying to find that elusive pump. So far no luck but I do have a mechanic coming today as it happens and will ask him to find it.

Posted By: Gasman 2 on 03/05/10 09:20am


I would think you would have two brake light switches if you have air brakes and I believe that's what you indicated. Since modern air brake system are dual systems front and rear there they usually have two brake light swtiches. These switches are close together are wire in parallel with each other. In other words one could fuction without the other. With that said if one of the switches was defective and was in the closed postion and would now open when the brakes were released the second switch's fuction would be irrelevant.

Gasman 2

Posted By: frankdamp on 03/05/10 08:10pm

Frito Bandito - are you former Boeing Simulator Tech, Ron Eakins?

Allan Damp

(signature says Frank, but that's my middle name)

P.S. - Just looked up your profile and you're not! Ron's nickname came about because he had the same type of moustache as the cartoon character in the ads.

Frank Damp, DW - Eileen, location Anacortes, WA, now retired RVers (since Dec 14)
Dog - 1 Lab, a yellow male, 13 yrs old July 2016.

Posted By: ziggywiggy on 07/04/10 09:54am

I have a 2005 Tiffin Phaeton with a Freightliner XC Chassis(38K miles). I am the third owner and I see in the maintenance history that the previous owner complained of the cruise control disengaging itself intermittently. I've had it for about 3000 miles and the cruise control quit all together. The yellow instrument light goes on and off as I turn the cruise on and off, but the cruise never actually works. I have checked the small vacuum pump and it is working fine. Other than that I don't know what to check. I can't even find a "cruise control" fuse. There is very little documentation from Tiffin and I can't spend days playing phone tag with their service department every time I have a question.

Can someone post a photo of this BACK-UP LIGHT SWITCH" Part No. TDA RBE 13250 so I'll know what I am looking for?

Thanks for any help...

Posted By: fcooper on 07/04/10 09:00pm

ziggywiggy wrote:

Can someone post a photo of this BACK-UP LIGHT SWITCH" Part No. TDA RBE 13250 so I'll know what I am looking for?

I don't have a picture available, but if your chassis is like my 2000 freightliner xc, you'll find both brake light switches on the bottom of the brake treadle. You'll have to crawl under your coach, get under the driver's floor area, and look up. It's a long reach...I can barely touch the bottom of the treadle. The two switches each have two wires attached. I think this must be a common failure item, because I've had one of mine replaced and it had failed like the earlier post described.

Fred & Vicki
St. Augustine, Florida

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