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Loose small hose coming out from under battery need help
Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!ZJ (93-98), WJ (99-04), WK (05+)
All ZJ/WJ/WK specific tech questions asked here!
Okay, for some reason my front diff vent hose has got a vent cap fitting on it's end that's clipped to the top of the front shock stud in front of the ABS module. The other end goes to a plastic fitting pressed into a hole in the front diff near the top of the housing on the back side of the cover flange. In my case, snow kept pulling the fitting out of the diff, so I put vise-grips on it and hammered on them to reseat it. Hopefully, it'll stay in this winter, otherwise I'm going to have to thread it for a brass fitting.
The battery tray drain hose was just conjecture on my part. It's good to know my thoughts were correct. I was replacing the battery on my lawn tractor at that time, LOL!
BTW, I found out why they put that fan relay under the headlight. It was an attempt to isolate it from engine heat and cool it because it gets hot itself in operation. If it's relocated on the other side of the radiator support, it will overheat.
Defrost is the default setting for the heater control if all vacuum is lost. There should be a check valve in the vacuum line near the intake manifold that seals off the line in cases of low vacuum such as in acceleration. That's when the vacuum reservoir comes into play. Just checking my FSM, there are 2 check valves in the system. The other one is in the black supply hose on the HVAC unit behind the floor vent duct. This is on non-automatic climate control units. It's supposed to hold HVAC settings during short periods of high engine load.
This Full Service Manual is the best investment I've ever made! If you've got $8 to spare, download one for your jeep from pacificcoastmanuals.com. It's 93mbs of compressed pdf files on every system in your jeep. I have learned A LOT about my WJ and WJ's in general. Another good website is wjjeeps.com
Hi Dave,
Thanks once again. I revived it as I come back to this vacuum issue off and on. When I get frustrated iwth something I tend to leave it and come back as I dont work well with frustration and don't think things through. And I've put in countless days into this problem.
What I found was the hose and fitting is not in the diffrential well at all. It was half out (the plastic fitting) and the hose was off it. Is this part of the vacuum that could cause this??? If so we may have found it.
Thanks for the manual info. Yes I will pay 8 dollars.
LOL!!!!!!
I've got the Haynes book. But let me tell you when it comes to vacuum it is worthless for that. Absolutely worthless book. It's great for basic stuff to reference but not for this.
Thanks to you and anyone who has helped find this.
But yes battery tray drain and drain line is what the hose was.
I finally pulled the dang tray. I notice on previous jeeps the reservoir was udner it . not on this one I just clarified that to soemone else who thought it was. But WJ and later apparantly it's just a drain line for the tray. The reservoir I saw it in the bumper and if you remove the headlight and tray you'll see it and can reach the hose on it too to check it that goes to that tee behind the headlight then to the cruise control actuator then goes off to the tee on the passenger side firewall , then a tiny line goes into firewall to AC control, then goes across firewall to intake manifold. I think I got this right?
But that line now looks good. So the problem has got to be somewhere else now??? Thanks. Diffrential hose and fitting is extremely questionable at this point. If this is part of the equation we may have found it.
Thanks for chiming in.
I found the vacuum problem with the AC shifting to defrost on inclines , hills and acceleration. There was a TSB that is you have no vacuum leak to perform the TSB and put in a one way check valve on the small black line that goes into the firewall at the tee junction.
BINGO. That fixed it. Cruise control and AC vent is no longer shifting to defrost on incline or hard acceleration. I just did my freeway ride in 90 degree weather here with AC working great and cruise control working.
Geez vacuum issues are a big pain!
For future reference do a search on TSB WJ 242499.
Apparantly this car has done it since day one and it was never taken in for the fix.
It seems to affect WJ's and other Chrysler Jeeps from all the searching on the matter.
But, fixing the vaccuum first is key otherwise the TSB wont work anyway if there is in fact a leak. No leak the check valve fixes it.
Here's a link to the download for anyone else it's 9 dollar fix at autozone.
By the Dorman HELP univeral one way check valve and the DORMAN vacuum line hose connector kit (you'll need it for the small line to adapt to the 1/4" connection).
Edit post this is what the hose under headlight is connected to
The lost hose under the head light on 99-04 WJ is this looks like a bottle I guess but this is what it connects too that runs to the vacuum box under light hopefully this helps
So I found a pic of where it connects
Last edited by Mark Anthony Sanchez; 06-10-2018 at 05:37 PM.
Reason: Didn’t have full info
Okay Mark, what that picture shows is the connector for the fan relay which isn't there but mounts in those 2 rusty holes on the left of the pic, and the hose that goes to the vacuum reservoir that would be beyond the bottom of the pic. The reservoir on the WJ is a weird shaped plastic box that's kind of triangular and flat. If you do install a fan relay, make sure the surface is clean because it gets hot and has to transfer it's heat to the body or it will burn out quickly. In reality it should be mounted on an aluminum plate, but Jeep never thought about that. The reason they mounted it under the headlight was to cool it with the air of forward motion.
Without the vacuum reservoir, the heater controls and the cruise control won't work and it's a vacuum leak that the engine has to contend with.
08-22-2016, 05:55 AM
