Ignition Problem
I own a 1999 Monaco on a Ford chassis with a V-10 engine. The starter will not engage from the ignition switch. I can turn the ignition switch to the “on” position and jump the starter and the engine cranks okay. A mechanic has worked on this problem several times in the last two months. He has replaced and/or bypassed relays and other switches in attempts to find the problem. So far he has not been able to fix it. Can you provide any information on what could be causing this problem?
John Harrington, F264609, Kinston, North Carolina
Has the mechanic tested the starter circuit from the key? It sounds to me as though that is where your problem lies. You may need a new ignition key assembly. The mechanic should be able to pull it and bench-test it. If the key assembly tests okay, then the problem most likely is located in the wiring harness.
No Backup
I own a 1997 National RV Tropi-Cal 36-foot motorhome built on a Chevrolet P-30 chassis. After driving it 1,400 miles in three days “” the last day covered 400 miles in 80-degree weather “” I pulled into the RV park and had to put the motorhome in reverse to back into my campsite. The engine sounded as though it had a load on it, but the motorhome wouldn’t move in reverse. I gave it more gas and it still didn’t move, although the motor sounded like it was trying hard. The motorhome acted as though the emergency brake was on, but it was not. I shifted it to park, then to drive, and it would go forward but would not move when I shifted again into reverse. I shifted it to first then to reverse several times, and it still wouldn’t move backward, only forward.
I did apply the emergency brake “” to see whether it somehow might have engaged by itself “” and released it two times. (By the way, I had not used the emergency brake for months prior to this.) I then shifted it into reverse again, and it finally moved backward, and the motor did not seem to be loaded as before. I parked it and have not tried backing it since.
In a previous issue of FMC, I read about a relay that controls the parking brake on the driveshaft. It was suggested that the relay be replaced to correct the problem. But I don’t remember what that was or where the relay was located. Could you help me troubleshoot this problem and also locate the position of that relay on my motorhome for future reference?
James Grala, Grand Rapids, Michigan
Issues with the automatic parking brake system used on Chevrolet P-Series chassis have been discussed within the pages of Family Motor Coaching magazine numerous times, including several instances in which the problem was nearly identical to the one you describe.
To understand why this problem occurs, it might be helpful to understand how the automatic parking brake system works. The auto-park brake system was used on all P-Series chassis equipped with Hydra-Matic 4L80-E and 4L85-E transmissions and with gross vehicle weight ratings above 15,000 pounds. The system utilizes a drum-type brake mounted on the rear of the transmission. When the brake shoes are applied against the drum, they stop rotation of the prop shaft, which keeps the rear wheels from rotating. The brake is applied when the shift lever is put in the “park” position and released when the shift lever is moved to any other gear position. A spring-loaded chamber mechanically applies the brake, and a hydraulic cylinder that obtains pressure and flow from an electric-powered pump releases the brake.
The June 1999 issue of Family Motor Coaching included a letter from Bob Farrow, in which he related the problems he was having with his 35-foot Dolphin motorhome built on a Chevy chassis. In the letter he wrote, “The “˜auto park’ engages and won’t allow the “˜reverse’ gear to engage.” He mentioned that this would occur generally after driving for some time. A follow-up to that letter was sent in by Burton Gotshall, who owned a 1997 Sea Breeze on a P-Series chassis and was having the same problem getting his motorhome to move in reverse. Mr. Gotshall wrote that he took his motorhome to a Chevrolet dealership and was told that the problem was an open shifter position switch, which was replaced. FMC technical correspondent Jay McClure elaborated on Mr. Gotshall’s letter with the following information:
“The 1994 through 1998 electric auto-park brake systems all use the cam-actuated switch, which is located under the driver’s floor board. Access to the switch for adjustment or replacement requires removal of the left front tire along with the side panel. The adjustment is outlined in Chevrolet service bulletin 46-50-08 dated November 1994 and in the Chevrolet shop manual.”
In the August 2004 “Technical Inquiries” column, a product service technician from Workhorse provided detailed information about the system in “Auto-Park Brake Questions” (page 24). He explained why the parking brake fails in the safe mode, meaning it activates or remains activated in the event of any failure within the system. Possible causes include the loss of power to the solenoid valve, from a dead battery or loose battery connection, for instance; loss of fluid pressure resulting from leaks in the system; or contaminated fluid.
The explanation also noted that connecting add-on electrical devices to the same circuit or wiring as the auto-brake has been known to cause problems. These can include aftermarket backup cameras, obstacle sensing devices, and backup warning devices. Owners are instructed to make sure these types of devices are fused separately if wired to the backup lights, since the backup lights are often wired through the neutral safety switch that is necessarily fused on the same circuit as the auto-park brake, as this is the switch that actuates the brake.
Workhorse recommends a yearly inspection of the auto-brake system for loose connections, corrosion of components, adjustments, reservoir fluid level, fluid condition, and system operation. The system also should be inspected to make sure added equipment is not installed on the same circuit or wiring as the auto-park brake. An electrical overload resulting from such added items has been known to cause the parking brake to apply or not release.
Considering the age of your motorhome, the fact that you’ve already encountered a problem with the vehicle not moving in reverse, and the possibility that another failure could leave the motorhome disabled, it would be prudent to contact a Workhorse service center and have the auto-brake inspected and repaired if necessary. To locate the nearest service center, visit www.workhorse.com.
Equinox Odometer
Is there a fuse I can pull to avoid adding miles when I tow my 2010 Equinox?
Don Miner, F340004, Allegan, Michigan
Follow the instructions for recreational towing in the Equinox’s owners manual. You’ll find that the setup procedures indicate that fuse #32 needs to be removed to prevent battery drain. In the past, mileage accumulation was an issue with late-model vehicles that used mechanical odometers. But vehicles with electronic odometers typically do not add miles when the vehicle is being towed with the ignition off or in the ACC position.