Loose vacuum hose and connections?

Tiny
00RING
  • MEMBER
  • 1986 DODGE RAM
  • 5.1L
  • V8
  • 4WD
  • MANUAL
  • 58,000 MILES
There is a loose end of a vacuum hose near the heater box that appears to go under the left of the truck and joins the hose bundle that loops over the transfer case and back up the right side. There are also a pair of vacuum solenoids on the right inside fender that are not connected to anything on two of the hose nipples. The transfer case does shift properly, and the engine seems to start and run well. I will include photos.
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Monday, April 7th, 2025 AT 2:50 PM

8 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,144 POSTS
Thanks for the images. The empty hose connections on the control solenoids have a small air filter that falls apart, so the is normal. The vacuum line behind the engine can go to the EVAP system, I would use a flashlight to see where the other end goes. Here is the vacuum line diagram for the transfer case. Check out the images (below).
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Tuesday, April 8th, 2025 AT 10:46 AM
Tiny
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Where exactly do the missing filters go on the control solenoids? What do the 2 control solenoids do? Could my loose end belong connected to one of them?
Which part exactly of the evap system could this loose end go to? I have tried to trace the loose hose under the truck, but it becomes impossible as the hose bundle crosses over the transfer case (not enough clearance to see or feel an individual hose, they are all the same black color)
If the 4wd works (axle shifting vacuum lines all attached and working) and I found the transfer case vent tube cap end near the back of the engine, what else is there as far as hoses running under the truck and over the transfer case?
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Tuesday, April 8th, 2025 AT 2:33 PM
Tiny
KEN L
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There are small filters that go over the ends of the solenoid ports made of foam rubber. These solenoids control the EVAP system and heat valve. I marked the diagram below to show you what they do and their port side for the foam cover. The diagram I included in the first post shows you the vacuum lines for the 4wd system.
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Wednesday, April 9th, 2025 AT 10:43 AM
Tiny
00RING
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Thanks! I found clearer diagrams and found the loose line is a vent line for the T-Case vacuum switch. I cannot find the "marked diagram below" you mention above.
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Wednesday, April 9th, 2025 AT 12:36 PM
Tiny
KEN L
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Good job, sorry the image did not load. Here it is. So, is the problem fixed?
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Friday, April 11th, 2025 AT 9:09 AM
Tiny
00RING
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Issues are resolved except I cannot find a o2 sensor to replace though I've searched the entire exhaust system.
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Friday, April 11th, 2025 AT 10:06 AM
Tiny
00RING
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The entire exhaust system
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Friday, April 11th, 2025 AT 10:07 AM
Tiny
KEN L
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Sorry, we only handle one problem per thread, please post your new question here, you must be logged in.

https://www.2carpros.com/questions/new

Cheers, Ken
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Friday, April 11th, 2025 AT 10:11 AM

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