1993 Gulfstream electrical problem


  #1  
Old 08-01-06, 12:28 PM
R
Member
Thread Starter
Join Date: Aug 2006
Posts: 2
Received 0 Votes on 0 Posts
Unhappy 1993 Gulfstream electrical problem

I am trying to help a friend troubleshoot an electrical issue. He has a 1993 Gulfstream Scenic Cruiser motorhome. It’s a 33 foot diesel pusher built on a Spartan chassis with a Cummins turbo diesel and an Allison transmission. The specific problem occurs when he is hooked up to “shore” power. There is a large solenoid on the chassis which serves to engage all 4 batteries (chassis and coach) when you throw a toggle switch while starting. While hooked up to shore power this solenoid engages and releases every 30 to 60 seconds on its own. He replaced the main power inverter and that did not stop the problem. A year or so back he also replaced the solenoid and it did not solve the problem. We have put a 12 volt test light on the two light wires leading to the solenoid. On one of the wires the test light glows very dully. It appears he has a constant low voltage getting to the solenoid which seems to build in the solenoid until it actuates, which in turn has also caused his batteries to drain when parked between roadtrips. Any assitance would be greatly appreciated.
 
  #2  
Old 08-01-06, 02:12 PM
A
Member
Join Date: Oct 2004
Location: Ontario
Posts: 539
Received 0 Votes on 0 Posts
start by disconecting the wire and see if the power is actuly on the wire or comming from the soinoid if it is the wire try and trace it to see what it is conected too if the solinoid start taking wires off too see when voltage disapates it still could be a faluty solinoid let us know results
 
  #3  
Old 08-16-06, 07:42 PM
H
Member
Join Date: Jul 2005
Location: usa
Posts: 33
Received 0 Votes on 0 Posts
did you figure this out yet?
that large relay is a emergency start relay.
and it sounds like you are describing the workings of a BIRD relay. that stands for Bi Directional Isolator Relay Delay. What the bird relay does is it looks for something like 14vdc ( I don't remember right off the top of my head the exact voltages) on either the House side, or the chassis side. It then assumes that you have spare capacity to charge the other set of batteries and sends a 12vdc pulse to the emergency start relay to activate it. It then drops this pulse voltage to a much lower voltage like 5 vdc or something like that, this low voltage holds the relay closed and sends juice from one side to the other. It then waits for the 14vdc to fall to like 12.8 or something close to that and it then assumes that you no longer have the necessary spare capacity to charge the other batteries and opens the circut to the emergency start relay.
Now for the fun part. I would guess that you likely have one of three things wrong. At least this is where i would start looking. first. I am guessing that you plug the unit in and the chassis batteries go dead while parked. This speaks to me of a drain on the chassis batteries that needs to be located or possibly bad batteries or maybe bad connections to the batteries, a bad Bird relay, A bad ground or poor connection somewhere in the system could also cause it to act up. I would first check the chassis batteries for a drain, ck connections to the chassis batteries and if possible load test them. then move on from there.
The Bird Relay is a black box about 3"x4" and about an inch thick. they tend to be located in electrical compartments.
It sounds to me like the voltage is comming up, the Bird relay activates the start relay to send charge the chassis batteries, then the voltage drops off and the bird relay opens the circut and the start relay drops out. if so the bird relay is doing its job and the problem is otherwise.
This should get you going again and hopefully lead you to the problem if you haven't already solved it
 
  #4  
Old 08-17-06, 06:46 AM
R
Member
Thread Starter
Join Date: Aug 2006
Posts: 2
Received 0 Votes on 0 Posts
Success.....or at least a begining

Saturday I spent the afternoon working through the electrical on his motorhome and wanted you to know I had some success. I used my ohmmeter to check the voltage at the starter batteries and it appeared I had 24 volts ( 2 @ 12 volts each). I searched for bad grounds as you had suggested and evidently found one. Each time I would make a change I would try to start the motorhome so I could see when I made a difference. A chassis ground where two wires connected was the last area where I removed, cleaned and replaced the wiring. After this change the motorhome started!

This connection was like a “splice” on the negative leads to the starter batteries. At the splice they used “toothed” washers between the two wire terminals and under the bolt to make sure they didn’t come loose due to vibration. My guess is the toothes were limited points of contact and they had rusted.

Whatever the case, I went out Sunday morning before church to check it again and it started right up. Hallelujah!!

I am just getting into tracing the small wiring that I told you carried a low voltage charge that was activating that large solenoid. That appears to be a separate problem, not associated with the starting problem. I did find out the charge is in the wiring before the toggle switch at the dash so I’m working backward through the maze of wires to find the source. This is a much smaller issue than the starting problem.

Thanks so much for your guidance.
 
  #5  
Old 08-17-06, 01:21 PM
H
Member
Join Date: Jul 2005
Location: usa
Posts: 33
Received 0 Votes on 0 Posts
hmm that should have been 13.4vdc not 14 my mistake..
24vdc??? sould only be like 12-13.5 or so I dont believe that chassis is a 24vdc system.. sounds like you are making progress though so good luck
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: