HVAC and cruise not working

SubLime

SubLime

TJ Enthusiast
Supporting Member
Joined
Apr 7, 2019
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145
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WI
Cruise and HVAC died this weekend. Cruise control on light doesn’t come on from the steering wheel. Nothing from the HVAC setting or fan.

Fuses look ok, vacuum port is plugged in as pictured, that is the correct plug, right?

Next, unplug and check for vacuum while running?

IMG_6115.jpeg
 
There are ways to test it with it running but I've never had any luck. I put a vacuum pump on the lines and eventually determined that I had some rotten lines and also some faulty vacuum check valves (there are two, one is actually pictured there, and the other is right near where the lines go through the firewall at the heater core.
 
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hear said:
There are ways to test it with it running but I've never had any luck. I put a vacuum pump on the lines and eventually determined that I had some rotten lines and also some faulty vacuum check valves (there are two, one is actually pictured there, and the other is right near where the lines go through the firewall at the heater core.
Click to expand...

Thanks, guess I'll have to make a shop appointment tomorrow
 
This should be the vacuum hose. It is the same vacuum hose that feeds both.
On the side of the intake manifold, it splits to cruise control module and to HVAC system.
 
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TexasTJ2004 said:
This should be the vacuum hose. It is the same vacuum hose that feeds both.
On the side of the intake manifold, it splits to cruise control module and to HVAC system.
Click to expand...


So the connection in the picture I attached? Take it apart and check for splits?
 
SubLime said:
So the connection in the picture I attached? Take it apart and check for splits?
Click to expand...

honestly any/all of the vacuum hoses could be bad. I had a weird HVAC problem and discovered that my hoses would literally crack if you so much as touched them, then found the check valves were no good, then I discovered the vacuum reservoir under the battery was unhooked. The vacuum pump is going to be much cheaper than the shop you're going to take it to. Heck, just blindly replace all the lines & check valves and you'll be in for less than $20.
 
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SubLime said:
Cruise and HVAC died this weekend. Cruise control on light doesn’t come on from the steering wheel. Nothing from the HVAC setting or fan.

Fuses look ok, vacuum port is plugged in as pictured, that is the correct plug, right?

Next, unplug and check for vacuum while running?

View attachment 442459
Click to expand...

If you have compressed air, you can attach a smoker device to the manifold (I connected through the brake booster hose) to expose your leak. That’s how I located massive leaks at the ends of the butterfly valve and an HVAC connector disconnected.
 
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SubLime said:
Cruise and HVAC died this weekend. Cruise control on light doesn’t come on from the steering wheel. Nothing from the HVAC setting or fan.

Fuses look ok,

View attachment 442459
Click to expand...

The problem you are experiencing would not be vacuum related.
Loss of both HVAC control and Cruise Control controls with loss of the CC dash board light is most definitely electrical.
To assist in troubleshooting you can download the Factory Service Manual for your year TJ in a PDF from the TJ Resources Section.
Check in section 8W-33-2 and 8W-42-1 to determine where the problem is.

https://wranglertjforum.com/threads...ice-manuals-fsm-technical-documentation.4618/
 
Last edited:
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CharlesHS said:
The problem you are experiencing would not be vacuum related.
Loss of both HVAC control and Cruise Control controls with loss of the CC dash board light is most definitely electrical.
To assist in troubleshooting you can download the Factory Service Manual for your year TJ in a PDF from the TJ Resources Section.
Check in section 8W-33-2 and 8W-42-1 to determine where the problem is.

https://wranglertjforum.com/threads...ice-manuals-fsm-technical-documentation.4618/
Click to expand...

Winner, winner. It turns out the two problems were not related.
Mechanic got a P1596 code, ended up replacing the clock spring.
And the blower motor died, replaced that also. Things are back to normal.
 
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SubLime said:
Winner, winner. It turns out the two problems were not related.
Mechanic got a P1596 code, ended up replacing the clock spring.
And the blower motor died, replaced that also. Things are back to normal.
Click to expand...

And to make it better, the airbag dash light started coming on about a week before the cruise died, well duh, the clockspring also fixed that..
 
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