2000 Monaco knight brake lights

[Guentha]

I was recently told neither of my brake lights work on my 2000 Monaco knight. The coach is fairly new to me and the previous owner has touched almost every wire with as far as I can tell, no electrical knowledge at all. I have spent well undoing his "fixed"

I am down to just a couple thing but break lights are now first on my list. I have check every fuse that makes sense under the driver side. All good. The bulbs look good but I haven't rules out 2 bad bulbs. Not out of the question as I have no idea how long I haven't had break lights. Turn signals all work.

I have also attached a photo with 2 things circled. Any clue what this random wire and missing relay are for?

Also sti looking for any info on how the vacume generator is powered. Never found a fuse and there is no power on the line ever so I don't have ac controles. Just defrost.

[MrMark52]

Since your turn signal lights work then it’s probably in the brake light switch as most turn signal lights are the same light as the brake light.

You really probably need to get both the coach chassis and Monaco coach wiring diagrams. If your lucky, you may find for your year, but if not look for anything near the same year, or any Monaco built in that range of years - most coach manufacturers build very similar panels and upgraded the higher end the coach is.
But I’m. Ore inclined to say your problem at this point is probably chassis related as the coach builder usually does nothing more than extend the dash wiring.

[153stars]

A little older than yours but on mine RH,LH,EM flasher & Brake all have own relay at rear firewall, you may have a box instead. Spent a few hours to figure this out before trip home after purchase. The brake relay terminals were dirty, 95 used wires and spades ,not relay sockets. Do you have wiring diagrams.

[Guentha]

Originally Posted by MrMark52

Since your turn signal lights work then it’s probably in the brake light switch as most turn signal lights are the same light as the brake lights

I had the same thought. 2 lights failing seems odd and the issue must be upstream. Fuse was first thought but nothing seems to be blown and brake switch was second thought however the breaks do disengage the cruise control leading me to think the break switch must work.

I wrong to think this?

[MrMark52]

Originally Posted by Guentha

I had the same thought. 2 lights failing seems odd and the issue must be upstream. Fuse was first thought but nothing seems to be blown and brake switch was second thought however the breaks do disengage the cruise control leading me to think the break switch must work.

I wrong to think this?

Brake switches are normally 2 pole, not single pole. One pole for the lights, the 2nd for cruise.
They could get the same function with a single pole brake switch driving a double pole relay, but it’s highly unlikely (too expensive).

You know the wiring to the lights is good if the turn signals work. So it’s either the brake light circuitry or flasher circuitry. Being as the PO fooled around with the wiring, the blinker may have been compromised as well.

[twinboat]

Air brake equipped coach's will have 2 brake light switchs on, or near the treadle valve. That's outside the firewall under the brake pedal.
Look for 2 identical switchs with jumper wires between them.

[Guentha]

Originally Posted by twinboat

Air brake equipped coach's will have 2 brake light switchs on, or near the treadle valve. That's outside the firewall under the brake pedal.
Look for 2 identical switchs with jumper wires between them.

I haven't had time to go look at the coach yet but I have an air parking break but my regular breaks are hydraulic. Should there still be 2 switches on the back of the firewall?

[DennisZ]

I’m having a similar issue with my coach, if i gently apply the brakes, the lights will not come on and the cruise will not disengage. If I give a hard, fast tap, the lights come on and the cruise will disengage. It seems like with lower air pressure, the coach not running, the work most of the time. I looked at the chassis schematic, I see the 2 switches, but I can’t find where they get a signal to the ECM to disengage the cruise control, any thoughts.

[YC1]

The missing relay could be for DRL. I would not pop a relay into it without a schematic and full understanding.

It could be an alternator fail light relay as well but I have real doubts about that.

Before fighting things like wiring, take a close look at your "brake lights". Are they separate bulbs from the turn signals???

It would not be crazy to think you have two bad bulbs. It happens. Checking the voltage on the socket is advisable or at least at some wire on the back. A 12 volt test light is probably the best choice since it will put a load on the circuit.

As suggested too, there may be some fuses or relays in a rear compartment.

Check around and post some pictures if you find such panels.

[Wrapped]

Are your turn signals top amber and brake bottom red lenses or only 1 red lens. Are you checking brake lights while parked if so you need air pressure for brake lights to work on some coaches.

[Guentha]

I have air parking brakes but hydraulic main brakes. From what I can see I only have 1 switch, and its on the pedal under the dash. the part looks to be a GM D850A and is only $15. going to give it a shot for that price.

as for needing air pressure, I don't think I do for my system but I was first told about it while driving in Canada and a person stopped me after a long windy hill section and told me he never saw any break lights. I definitely would have had air as my suspension was working.

I do have a separate turn and brake light enclosure. turns do work but they are wired perfectly. breaks have their own enclosure and bulb. It looks to be a dual filament so must also be my running lights. on inspection, all the filaments look good.

[Guentha]

Sorry for the double post. I could find a way to edit my last message.

I pulled the brake switch and it works. it has 4 contacts a set of normally open and a set of normally closed and they are both good. I have now double-checked every fuse I can find. (under the driver in the lower compartment, the back of the coach in the bedroom, the ECU fuses in the rear battery compartment.) If there are more I can't find them

really seems like it should be in the panels under the driver. there are fuses for things like markers and turn but nothing brake related. Regardless I check every single fuse. only one bad and it's for something about step iso or something and it blows immediately when I put a new one in and my steps come in. however my steps work great so I don't know if this is just the date that pulls them in if its in ger no matter what but I don't need it and it's broke somehow and a job for another day.

Bulbs are good and I tested for power with a multimeter and got nothing. Daytime running lights do work and they are on the same bulb (different filament).

I am tempted to put 12v on the brake switch line but I assume it's a ground that is switch and now the positive.

[YC1]

Check your rear compartments for any fuse boxes and relays.

The right rear compartment on mine has some there. Different year but it is worth a close look.

As for editing posts. You have a limited time to do so. If really desperate you can "notify a moderator" and they can help you.

[twinboat]

Originally Posted by Guentha

I haven't had time to go look at the coach yet but I have an air parking break but my regular breaks are hydraulic. Should there still be 2 switches on the back of the firewall?

No.