Cruise Control and Faulty Dash AC Problem

[Jackm]

Has anyone ever encountered a problem with the dash AC when using cruise control? In our 2004 Brave (W-20 chassis), we lose the AC whenever we use the cruise control. At first, I thought it might be a slipping belt but upon inspection, the belt is fine. It appears to be a glitch of some type. The technician asked us if the fan switched to defrost (when the AC quit working) but I didn't notice. Thanks.

Jack

[bsinmich]

I noticed a different one with my cruise this past summer. When the cruise was on and I would turn on the wipers the cruise would drop off. This would only happen when the headlights were on. If I turned off the headlights everything was normal. I am beginning to think there is no normal on these things. The rain did keep the brakes from overheating so there was a good effect also.

[wa8yxm]

On a gasser both Dash Air and Cruise share one thing.. A Vacuum line.. If you have a leak in your vacuum system then if the vacuum goes low

1: Cruise control will fail to work
2: Dash air will switch (ON GM Products) to Air Conditioner vents

(I don't know what it does on others, but since Defrost is the most important function.. One can but assume it should be the "Default" for lost air)

So Look for a broken, hose on your vacuum lines somewhere

NOTE: both CC and Dash air, on GM's are tapped off the brake booster at the booster right at the check valve.

[wa8yxm]

For Bsinmich.. Sounds like a ground fault to me

The cruise control measures voltage on both sides of the brake light switch

12 volt on the "hot" side is needed for the Cruise to engage

If there is voltage on the "Load" (Light side) of the switch, it disengages

If your wipers share a groung with one of the lamps it may be feeding back via the lighs themselves and shutting you down.

Of course, there are many other issues that can kill it too.

I mean they tell you "Do not use CC in the rain" Perhaps somebody made it so you can't.

[Jackm]

A vacuum line sounds like a good start but I wonder if a leak wouldn't show up under other operating conditions. In other words, wouldn't a (vacuum) leak impact the AC or the cruise control at other times?

Jack

[dieselclacker]

Jack, your cruise control does not operate with a vacuum servo as older motorhomes do.

Dieselclacker

[Jackm]

Good point Dieselclacker. When I described the symptoms to a few technicians, they gave me that glazed over look you see whenever you present them with hard-to-diagnose electrical problems. It's too bad that RV manufacturers don't let you e-mail in specific questions to their technical staff. I'm sure someone at Winnebago or Workhorse has encountered something like this. The dilemma is the fact that I can't duplicate the problem in the shop. The RV has to be flying down the road for the (periodic) symptom to occur. Thanks for the comments though.

Jack

["007"]

Jackm your brake switch which controls CC,steps and brake boost pump may need adjustment. The plastic plunger wears down over time and can be extended by removing wire clips to it, two, and turning plunger to extend it or your brake pedal is not returning to its full release position. Zerk fitting on bell crank need grease.

[abarkl]

Quote:

Originally Posted by "007" Zerk fitting on bell crank need grease.

That is not true any longer. The faulty braking system in the Workhorse chassis motor homes is due to sticking brake calipers.

[edgray]

abarkl: This thread is about cruise control, and the return of the brake pedal certainly can affect CC operation. 007's suggestion to grease the bell crank zerk IS correct, and I cannot agree with your "no longer true" comment. IMO, any zerk can only benefit from an occasional shot of grease.

You are correct about the caliper pistons being determined as the "source" of the brake problem being discussed elsewhere, but that does NOT mean we should stop adding lube at all the zerk positions. ED

[abarkl]

But how do I remove the words "Workhorse Chassis Owner" in the avatar area of my postings?

I never asked for it and I don't want to be associated.

[edgray]

abarkl: your request has been handled.

As info, members can join or leave a "user group" by choosing an icon from the list shown while in their profile found under the user CP tab at the top of the page. ED

[Jackm]

Thanks 007. I'll check out the brake switch plunger. On my 2004 W-20 chassis, there is no grease fitting on the brake bell crank. I do plan on adding them this summer. To lube the bell crank, you have to manually access the inner workings by lifting some part (I read this in the Users Manual). I appreciate the suggestions. I'll give it a shot.

Jack

[wa8yxm]

Workhorse added the Zerk on the Bell Crank just prior to making my Motor home chassis (The MH is a 2005, the chassis was made Aug, 2004, per WH)

I checked