How do I troubleshoot cruise issues on DDEC III and S60?

belfert · August 13, 2008, 07:17:13 AM

Any idea how to troubleshoot a cruise control that won't set on a Series 60 with DDEC III?

This has been an issue about three times now, but so far it works after the engine is turned of and started again. It has never gone out on any long trips just on fairly short jaunts near home. I would like to get it fixed so it doesn't go out on a long trip.

Sammy · August 13, 2008, 07:23:31 AM

You'll need to check the cruise control parameters in DDEC with a ProLink,a wiring diagram for your bus, a DDEC III wiring diagram and I use a WTEC wiring diagram too.

Busted Knuckle · August 13, 2008, 07:36:25 AM

Ahhh, don't make short trips?

OK I knew wouldn't fly. I'd start with the manual and check wiring diagrams. Then find all the connection points and check for loose or sorroded connections. Also check for small single wire fuses near the batteries, I know on our DDEC Setras there are several and they are 12V circuits for the DDEC. I had a bad fuse holder there once and it caused problems with the fuel injection.

Also weren't ya taking it to JD for an annual service? Ask him about reading the computer and seeing if it has issues, or codes. Tell him whats going on, maybe they have seen this problem before.

Is it possible you have a brake light or retarder switch hanging up? If they are then the cruise won't work! FWIW

BK

Darn Sammy got his post in first! LOL!

belfert · August 13, 2008, 08:39:01 AM

The issue started (again) after I took the bus to JD yesterday for annual service. I talked to JD today and he said there is unlikely to be any codes if no check engine light. Jd did talk about possible brake switch issues and said the brake light switch is seperate from brake switch for the cruise.

Really hard to diagnose unless it breaks 100%.

Busted Knuckle · August 13, 2008, 08:46:13 AM

Quote from: belfert on August 13, 2008, 08:39:01 AM
The issue started (again) after I took the bus to JD yesterday for annual service. I talked to JD today and he said there is unlikely to be any codes if no check engine light. Jd did talk about possible brake switch issues and said the brake light switch is seperate from brake switch for the cruise.

Really hard to diagnose unless it breaks 100%.

What about tranmission reterder? Or does yours have one?

belfert · August 13, 2008, 10:13:20 AM

No retarder. I have jakes instead.

Cruise isn't critical to making my trip so this might go on the back burner.

blue_goose · August 13, 2008, 04:35:01 PM

There are two parts to the cruise control.
For the fast idle to work you have to have a ground at wire 531 and wire 543. For the cruise to work you only have a ground at wire 543. If you don't have a ground at wire 543 the cruise will not work. Are you getting a green light when the cruise enable is turned on?
Jack

belfert · August 14, 2008, 04:54:10 AM

I don't have any sort of light that indicates if cruise is on or off. All I have is a cruise on/off switch, momentary for set cruise, and a momentary for resume/accelerate.

Ground is a very likely problem as I have had grounding issues in the dash.

blue_goose · August 14, 2008, 05:57:58 AM

You don't have to have the light, but everything in the cruise works to ground. No ground No work!
Jack