1981 Itasca Sundancer mystery part

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  #1  
Old 08-21-17, 05:26 PM
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1981 Itasca Sundancer mystery part

Last night, my father-in-law brought me a part off of his motorhome that I was pretty sure was a relay. The socket where it plugs into the engine wiring harness (and, I'm told, the connector on the harness) was pretty badly burned, and the markings on the outside of the housing were obscured with corrosion/weathering. This mystery part came from the above-mentioned 1981 Itasca Sundancer; it was built on a chevrolet van cab-and-chassis, and has the 5.7-liter V-8 engine. A little research on Mitchell at a local garage revealed that it is the engine speed relay. The wiring diagram shows that one wire comes from the tach side of the distributor cap (HEI), two wires go to an engine speed solenoid, and one wire goes to ground. Looks like there's a servo involved as well. As yet, I have had no luck finding this part or its connector to allow me to effect a repair. The owner of the garage that let me use their Mitchell said I should just disable the circuit. Is this possible and/or advisable?
Update - my wife informs me that her father said the cruise control hasn't worked in some time. I would not be surprised to learn that this part is a component of the cruise control. However, he also says that when he turns the key in the lock cylinder, nothing happens, as in no dash lights, no clicking, no nothing. The battery was supposedly good and hot when he tried to start the vehicle. It sounds to me like he has bigger issues than the cruise not working. Problem is, I'm working 7 days a week and don't have much time off, so I don't have many opportunities to look at or work on his toys. Any advice as to where to start looking when I DO get a chance would be greatly appreciated. Thanks in advance - Chris
 
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Old 08-21-17, 10:16 PM
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Welcome to the forums.

You missed an important word.... idle. That is an idle speed control relay. It controls the idle motor. That should not cause the engine not to crank.

I don't believe it controls the cruise either.

Couldn't find much info online in regards to that relay. I was using G-30 as the model but that may be incorrect. I found 1981 GM vehicles using it but no vans.

You could replace that relay with a Bosch or generic Bosch type relay. You will need to check current draw of motor to find out why everything melted. Possibly the motor is shorted.
 

Last edited by PJmax; 08-21-17 at 10:33 PM.
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Old 08-22-17, 06:01 AM
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Thanks, PJMax. I'm pretty sure I would have caught the "idle" if it had been on the diagram, but the Mitchell program looked kinda old, so... I can't see how it would keep the engine from turning over and starting, either. If I leave the relay out until I can find a suitable replacement, dad should still be able to drive it, right? He really only needs to take it to get its safety inspection so he can renew the registration.
 
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Old 08-23-17, 01:14 AM
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It should start and run but may not idle very well.

There's a chance that the fuse that controls that relay may have blown and possibly something to do with starting is on the same fuse.
 
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Old 08-30-17, 06:21 AM
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Finally! Got the engine to start and run last night. Problem turned out to be a missing ground strap under the ignition coil (has the HEI system), so it wasn't making spark. Also found that both fusible links at the starter solenoid had burned open. We also discovered that, at some point, the battery cables had been crossed at the battery. I suspect that caused or contributed to what happened next - when we got it started and shut it off, one of the new fusible links became pretty warm, and my FIL saw smoke coming from the alternator. SO, disconnect the ground and remove a VERY WARM alternator later, I need to know more than I do about the wiring for the alternator so we don't have a repeat on the replacement. I know the charge cable stays hot all the time, and the red wire in the two-wire plug stays hot as long as its fusible link is intact. But what about the brown wire in the plug? Hot with ignition on, to turn on the regulator/rectifier?
 
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Old 08-30-17, 06:33 AM
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1981 Chevrolet alternator wiring question...

I have a thread elsewhere in this forum about a 1981 Itasca motorhome built on a Chevrolet van chassis with the 5.7 V8. Got it to start and run last night after clearing up a number of issues (including backwards cables at the battery!), only to have a smoking alternator after we shut the engine off. I suspect that having the cables on backwards contributed to the alternator failure, but I want to make sure there's not a wiring issue before we hook up the replacement. From wiring diagrams I've been able to look at, it seems the charge cable is constant hot, and the red wire in the two-wire plug is hot as long as its fusible link is intact. What about the brown wire in the plug? Is it an ignition-hot wire, to turn on the regulator/rectifier? Or something else? I lose the wire going from the engine wiring diagram to any other page. I just want to make sure this is correct so we don't have a repeat; I'm getting too old for this kind of excitement. Thanks in advance for any/all input. - Chris
 
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Old 08-30-17, 10:12 AM
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....... Threads combined

The heavy red wire with the lug goes to the battery.
The smaller red wire should be the exciter wire and become live when the key is turned on.
The small brown wire should be for the idiot light. It's not always used and the alternator will run without it.
 
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