Help! ID switches on my air brake!

[Big Notes]

My first post here on IRV2. We have a new to us 1999 Itasca Suncruiser, DP on a Freightliner chassis, I think it's an XC.

We have had no brake lights or cruise control. Some research let me to ID and bypass some burnt diodes and replace the brake light fuse. All that is good, and I'll test the cruise tomorrow with a little skepticism.

In the meantime I'm trying to ID what looks like switches below the brake pedal unit. In the attached pics there are 2 pair, marked (1) and (2). Can anyone tell me which is what?

Like I tell my friends, "Hey I bought me a new project!"

Thanks
Jeff

[Skip426]

Welcome to iRV2 .

#1's are your brake light switches . One for each 1/2 of the air brake system , so if you have a half system pressure failure , you still have brake lights and cruise control shut down.

#2 , something I don't have on my F/L .
Is your coach equipped with ATC ( Automatic Traction Control ) or Brake system activation pressure gauges?
EDIT: Or it's possible they're the air tank pressure gauges are mounted remotely on your chassis. F/L marks their wiring with circuit numbers and names every 12>18" on the wire , if you can open the plastic wire conduit maybe you can read the circuit name.
Also a call to the Freightliner free help line will get you diagrams and schematics.
1-800-385-4357 have your serial number handy.

[ladagobago]

Originally Posted by Big Notes

My first post here on IRV2. We have a new to us 1999 Itasca Suncruiser, DP on a Freightliner chassis, I think it's an XC.

We have had no brake lights or cruise control. Some research let me to ID and bypass some burnt diodes and replace the brake light fuse. All that is good, and I'll test the cruise tomorrow with a little skepticism.

In the meantime I'm trying to ID what looks like switches below the brake pedal unit. In the attached pics there are 2 pair, marked (1) and (2). Can anyone tell me which is what?

Like I tell my friends, "Hey I bought me a new project!"

Thanks
Jeff

where did you find the diodes. I am getting into a similar problem of no brake lights, plus no return off fast idle or cruise control. I do have brake lights from the exhaust brake activation. You should ask the moderator to move your post to the freightliner forum. However Skip is very knowledgeable and has given some good help here.

[Big Notes]

Originally Posted by ladagobago

where did you find the diodes. I am getting into a similar problem of no brake lights, plus no return off fast idle or cruise control. I do have brake lights from the exhaust brake activation. You should ask the moderator to move your post to the freightliner forum. However Skip is very knowledgeable and has given some good help here.

Howdy laDagoBago! I found the diodes on red wires outside the main harness behind the steering column. They are pretty burnt up as you can see from the pics, and typically they're the first thing I noticed when looking into this problem and the first thing I discounted. In the one pic my temporary testing bypass is a brown and a green wire.

Skip, thanks for the info. I have a call to FL in my very near future, just gathering my thoughts before I get them on the line.

[Skip426]

Big Notes. Questions.
The white tag on the harness , can you read any printing on it ?
Any chance it said , diodes?
I have found one spot with a diode label on my harness.

With wiring diagrams and schematics in hand the , schematic will give you circuit #s and info on the use of diodes in the circuit. The diagrams will locate the diodes in the harness ( by circuit #) and the measurements from one harness junction to the next will narrow the actual location.
Measurements of the harness in the diagrams are metric , so you'll be getting to know your conversion table.

[Skip426]

Big Notes , I'd share my schematics and diagrams by e mailing them to you , BUT , in trying to help National owners of 98/99 F/L XC chassis coaches I've found there were major differences in the harnesses through the years in question and a F/L chassis book supplied with my coach shows a fuse box that is the same as the ones in the National coaches , but looks nothing like mine .
So it's best to have F/L match the wiring info to your serial number, and start from there.
Because you have the switches/sensors ? on the foot valve that I don't , I'm sure your wiring info will be way different than mine and Ladagobago's

[Big Notes]

Originally Posted by Skip426

Big Notes. Questions.
The white tag on the harness , can you read any printing on it ?
Any chance it said , diodes?
I have found one spot with a diode label on my harness.

With wiring diagrams and schematics in hand the , schematic will give you circuit #s and info on the use of diodes in the circuit. The diagrams will locate the diodes in the harness ( by circuit #) and the measurements from one harness junction to the next will narrow the actual location.
Measurements of the harness in the diagrams are metric , so you'll be getting to know your conversion table.

Yep, there was a white paper that was labeled "Diodes".

Thanks for the tip.

[Big Notes]

Originally Posted by Skip426

Big Notes , I'd share my schematics and diagrams by e mailing them to you , BUT , in trying to help National owners of 98/99 F/L XC chassis coaches I've found there were major differences in the harnesses through the years in question and a F/L chassis book supplied with my coach shows a fuse box that is the same as the ones in the National coaches , but looks nothing like mine .
So it's best to have F/L match the wiring info to your serial number, and start from there.
Because you have the switches/sensors ? on the foot valve that I don't , I'm sure your wiring info will be way different than mine and Ladagobago's

Understood. I do have a diagram from F/L and am daily making more sense out of it. Haven't found the switches on the foot valve yet.

[ladagobago]

Big Notes - thanks for the info. I will be getting into this as soon as we cool down a little. here is is 7PM and still 93 outside. I get about 2 hours in the morning but now it is still dark untill 7am.

I am certain that there should be some diodes in my MH. just have to find them.

What is big notes. Like whole notes vs eighth notes? or is it large print on 8x11 rather than on postem??

[Big Notes]

Originally Posted by ladagobago

Big Notes - thanks for the info. I will be getting into this as soon as we cool down a little. here is is 7PM and still 93 outside. I get about 2 hours in the morning but now it is still dark untill 7am.

I am certain that there should be some diodes in my MH. just have to find them.

What is big notes. Like whole notes vs eighth notes? or is it large print on 8x11 rather than on postem??

Bass Guitar == Big Notes on the Bottom

[Big Notes]

Update: Cruise control and brake lights work! I am stoked. On to other fixables....

[Skip426]

Originally Posted by Big Notes

Update: Cruise control and brake lights work! I am stoked. On to other fixables....

Great to hear that your on the road.

Did you install new diodes ? or are they still by-passed?

[Big Notes]

Originally Posted by Skip426

Great to hear that your on the road.

Did you install new diodes ? or are they still by-passed?

Been busy, MIA. I bypassed the diodes for now. The FL guy I spoke with doesn't recommend running that way; after further discussion it boils down to preventing interference between the brake and turn signals.

I got a part number from him and ordered 6 diodes. I splurged at $0.42 each...!

We have a bigger test today, an over nighter to Calhan CO for an outdoor shindig on 40 acres. Playing Trop Rock / Country with my friend Pup Morse this evening.

Jeff

[Skip426]

Originally Posted by Big Notes

I got a part number from him and ordered 6 diodes. I splurged at $0.42 each...!
Jeff

Sounds like a come on , probably $132.50 for S&H .