[redwheelwells]

Changing cabin air filter on 2018 Grand Cherokee Trailhawk with 5.7L Hemi, and other official factory Service Manual USB questions.

I recently sprang $$$ for the official USB factory Service Manual. From navigating, reading and re-reading the USB I understand it to say that you should disconnect (and isolate) the vehicle battery negative cable before changing the cabin air filter (to avoid unwanted deployment of air bags). If you disconnect the battery per service manual instructions, to reach the battery you must first position the passenger seat to the farthest upward/forward positions; if you do that, the lower seat cushion will not then allow downward rotation of the glove box bin sufficient to release it from the dash. (You are directed to remove said bin, etc. before removing the old cabin air filter.) Of course, If the battery is disconnected, you cannot move the passenger seat down/back enough to lower and remove the glove box bin!

Also, the official Service Manual directs you to disconnect the IBS (Intelligent Battery Sensor) before disconnecting(?) the negative battery cable (presumably this instruction was written when the design included a somewhat rigid/fragile IBS connector vs. the current one using conventionally-flexible wires?). See the image I took of my battery included here below.

Further, the official Service Manual provides somewhat confusing/incomplete torque specs and tightening order for various battery electrical fasteners. [For one example, in the battery installation section of the Service Manual, clicking on the internal “link” labelled “Torque Specs” takes you to a non-relevant page. For another example, the Manual directs you to tighten one battery terminal connector at the negative terminal first, and on the same page below says that such tightening order should not be done because it can break the IBS?! For a third example, the torque spec page I found through separate navigation did not give the torque spec for the 10mm IBS nut (I assume it’s the same 53 inch-lbs. as that given for the 10mm hex nut for the battery terminal clamp pinch bolt.).]

And yes, there are other confusing directions I won’t go into at this point.

How are service technicians expected to follow such confusing directions and specs?

Do I really need to disconnect the vehicle battery in order to replace the cabin air filter? If I do not disconnect the battery, and I use various vacuum cleaner smaller attachments to clean inside the filter housing area, might that rubbing/brushing activity generate, e.g., static electricity sufficient to trigger the airbags? Any other tips?

MANY THANKS IN ADVANCE, TRUSTED ALLPAR-ERS!

 

[Doug D]

I recently sprang $$$ for the official USB factory Service Manual. From navigating, reading and re-reading the USB I understand it to say that you should disconnect (and isolate) the vehicle battery negative cable before changing the cabin air filter (to avoid unwanted deployment of air bags). If you disconnect the battery per service manual instructions, to reach the battery you must first position the passenger seat to the farthest upward/forward positions; if you do that, the lower seat cushion will not then allow downward rotation of the glove box bin sufficient to release it from the dash. (You are directed to remove said bin, etc. before removing the old cabin air filter.) Of course, If the battery is disconnected, you cannot move the passenger seat down/back enough to lower and remove the glove box bin!

So, if I have read this correctly, the battery is located behind the front passenger seat (beneath the floor I presume)? And the cabin air filter is located behind the glove box?

I guess I don't understand how removing the cabin air filter could set off the passenger airbag unless there is a sensor positioned such that it could be hit while removing/inserting the air filter.

 

[redwheelwells]

So, if I have read this correctly, the battery is located behind the front passenger seat (beneath the floor I presume)? And the cabin air filter is located behind the glove box?

I guess I don't understand how removing the cabin air filter could set off the passenger airbag unless there is a sensor positioned such that it could be hit while removing/inserting the air filter.

Yes, battery is below front passenger seat, under floor. Cabin air filter is forward from glove box.

Yes, it is very common for the Service Manual to advise/warn about disconnecting vehicle battery (to avoid unwanted air bag deployment) before performing service/repair. Many of the electrical/electronic devices share circuitry, and as I understand it, differentiate functions via signal frequency---some sent and received by wire and some wirelessly; thus, something that might generate an unwanted signal to which the air bags respond is to be avoided. But like you I question how changing the cabin air filter could generate such a signal. The only thing I am thinking of as a possible cause in this case would be static spark(s) generated by rubbing certain materials together in the course of such servicing(?).

 

[valiant67]

I think the disconnect battery cable is just standard boiler plate text before almost every procedure. However, if they really expect you to disconnect the battery, I suspect they think you’d use a jumper box to temporarily power the seat to move it back (like would be done on a vehicle with a dead battery to move the seat to access and replace the battery).

 

[ImperialCrown]

Agree. It seems like an abundance of caution from Legal probably requires them to print that warning in the header for liability concerns. An airbag can go off like a shotgun and hurt you.
It is a generic warning. Most batteries are located under the hood. There are other ways to disable the airbags than pulling a battery cable.
It is interesting that the battery disconnect is mentioned in the Service manual procedure, but not in the Owners manual procedure.
I won't tell you NOT to disconnect power to the ORC or ABM first.

 

[redwheelwells]

Agree. It seems like an abundance of caution from Legal probably requires them to print that warning in the header for liability concerns. An airbag can go off like a shotgun and hurt you.
It is a generic warning. Most batteries are located under the hood. There are other ways to disable the airbags than pulling a battery cable.
It is interesting that the battery disconnect is mentioned in the Service manual procedure, but not in the Owners manual procedure.
I won't tell you NOT to disconnect power to the ORC or ABM first.

Thanks, IC! Lots for me to unpack here. Forgive my ignorance, but what are ORC and ABM?

I haven't found any other official documentation on how to disable the airbags; one side note is that they are said by the Manual to have a capacitor that once disconnected takes. what, maybe a minute to discharge before you proceed with possible airbag-triggering actions.

Fascinating to me that apparently the print form Owner's Manual, the online Owner's Manual (like the excerpt I think you included with your post), and the USB Service Manual all differ somewhat from one another when addressing the same basic service! (Not to mention the possible differences that could exist with the more-likely-updated SUBSCRIPTION online version of the Service Manual,) I forgot to check the online Owner's Manual; it appears to be more extensive than the print one! One thing about the online version of changing the cabin filter is the failure to direct one to remove the TRAY above the glove box compartment, apparently the failure to remove the tray first results in some abrasion to the old filter as you remove it, causing some dirt, etc. to fall into the dashboard-resident filter housing and some abrasion to the new filter as you install it.

What I'm thinking in conclusion is to:
1) Remove glove box and tray and filter cover
2) Remove old filter
3) Move passenger seat forward and upward
4) Disconnect and isolate negative battery cable and wait for capacitor to discharge
5) Vacuum out filter housing
6) Install new filter and cover
7) Re-connect negative battery cable
8) Move passenger seat downward and backward
9) Replace glove box and tray
10) Pray that there aren't too many lost "memory" functions that need to be re-set/re-learned.

I'd chance keeping the battery connected during the whole service procedure if I didn't vacuum out the filter housing.
Do these steps make sense?

valiant67, thanks, but I've heard of using a "memory-saver battery" when disconnecting a vehicle battery, but I seem to remember the Service Manual warning against these or other such jumper box devices due to possible damage to sensitive vehicle electronics.

 

[ImperialCrown]

ORC= Occupant Restraint Controller.
ABM= AirBag Module.

As far as losing memories & settings with a battery disconnect, you may need to reset your clock unless you have NAV (then the GPS will update the time). You may have to reset the Equalizer/Tone controls. The stations presets will stay.
The Express front windows may have to relearn full up and full down positions.

I lay newspaper on the passenger floor before pulling the tray. You can never tell what will fall out of the filter when you pull it out.

As for a temporary power-down, I was looking at the battery cable connection at its first stop from the battery at the PDC (Power Distribution Center). Access may be easier here that the battery post under the seat. These wires are 12v (+) , don't allow them to ground out on any surrounding metal .

 

[d150le]

Who approves these designs? Absolutely nuts.

Are they really sitting there telling engineers to design cars to be expensive and frustrating to work on?

 

[redwheelwells]

Thanks Again, IC, for your extra-effort help on this! I'm going to stick with my "10-Step" plan, though, because I suspect that the IBS might trigger something if I don't disconnect it and the negative cable at the battery as the "battery-disconnect" procedure. It looks to me like one of the IBS wires also connects to the Positive battery terminal, so I'm concerned that a different disconnect point/procedure could cause problems.

It's not like I expect to be changing the cabin filter that often. I've driven few miles per year since I bought the rig (less than 10k total so far), and I've checked the motor air filter twice---and it's far from dirty/occluded---so I figure it's similar with the cabin filter; no untoward smells coming out of the HVAC vents, either. Bottom line: I should be changing cabin filter so seldom that my "10 steps" including under-floor battery disconnect should be tolerable.

 

[redwheelwells]

Who approves these designs? Absolutely nuts.

Are they really sitting there telling engineers to design cars to be expensive and frustrating to work on?

At the risk of being banned by the site police, I'll just ask the follow-up question, "What external factors push the engineers to design cars to be so complex and expensive?"

 

[valiant67]

Who approves these designs? Absolutely nuts.

Are they really sitting there telling engineers to design cars to be expensive and frustrating to work on?

At the risk of being banned by the site police, I'll just ask the follow-up question, "What external factors push the engineers to design cars to be so complex and expensive?"

There are at least two benefits from getting the battery out of the engine compartment:
1) Better weight distribution.
2) Battery is not subjected to engine heat and can have a longer life.

 

[ImperialCrown]

The biggest offender in dirty CAFs is parking around trees. I've also had cars from out West that had a layer of orange dust 'everywhere'.

Automakers have trying to take the battery out of the engine compartment to get it out of the heat. You will still have jumper cable attachments under the hood.
LX puts them in the trunk. JA/JR/JX/LH puts them behind the front bumper. Sprinter is under the seat.
Batteries are heavy. The lower it is, the lower the center-of-gravity.

 

[d150le]

The biggest offender in dirty CAFs is parking around trees. I've also had cars from out West that had a layer of orange dust 'everywhere'.

Automakers have trying to take the battery out of the engine compartment to get it out of the heat. You will still have jumper cable attachments under the hood.
LX puts them in the trunk. JA/JR/JX/LH puts them behind the front bumper. Sprinter is under the seat.
Batteries are heavy. The lower it is, the lower the center-of-gravity.

Moving them away from the engine is one thing but making them difficult to access is not a well thought through solution.

I don't see why Leo Fenders design beliefs can't be translated to cars. "A quality instrument can be easily repaired."

My favourite cars so far have been the ones that have been cheap and easy to fix. A well designed car, can be easily repaired (or serviced).



Or could it possibly be that withholding procedure information, and making repair work tedious happens to be sickeningly profitable? No way, it's to protect the batteries that hardly last 3 years even when they're away from all that heat. 🤣

 

[valiant67]

Moving them away from the engine is one thing but making them difficult to access is not a well thought through solution.

I don't see why Leo Fenders design beliefs can't be translated to cars. "A quality instrument can be easily repaired."

My favourite cars so far have been the ones that have been cheap and easy to fix. A well designed car, can be easily repaired (or serviced).



Or could it possibly be that withholding procedure information, and making repair work tedious happens to be sickeningly profitable? No way, it's to protect the batteries that hardly last 3 years even when they're away from all that heat. 🤣

Have you had a car with a battery under the seat or inside the car or are you just complaining?
It's been far easier for me to change the battery in these unconventional locations. Granted, you do have to have auxiliary power to move the seat on a Grand Cherokee/Durango if the battery is dead but I've always had a battery charger since I got my first car.

 

[Doug D]

Or could it possibly be that withholding procedure information, and making repair work tedious happens to be sickeningly profitable? No way, it's to protect the batteries that hardly last 3 years even when they're away from all that heat. 🤣

Modern vehicles are designed for ease of assembly, not necessarily ease of service.

The easiest vehicles to service that I had were K-Car derivatives - '86 Chrysler LeBaron GTS and two Acclaims - '90 and '92.

Today's engine compartments are so tight I can see the reasons for relocating the battery to a "cooler" spot, though that may not be an easily accessible location.

FWIW - my son-in-law's Smart Car (when he had it) had the battery located directly underneath the passenger seat. The battery in the two Journey's we had were in front of the LF tire wheel well - not exactly easy to access.

 

[redwheelwells]

There are at least two benefits from getting the battery out of the engine compartment:
1) Better weight distribution.
2) Battery is not subjected to engine heat and can have a longer life.

The biggest offender in dirty CAFs is parking around trees. I've also had cars from out West that had a layer of orange dust 'everywhere'.

Automakers have trying to take the battery out of the engine compartment to get it out of the heat. You will still have jumper cable attachments under the hood.
LX puts them in the trunk. JA/JR/JX/LH puts them behind the front bumper. Sprinter is under the seat.
Batteries are heavy. The lower it is, the lower the center-of-gravity.

Moving them away from the engine is one thing but making them difficult to access is not a well thought through solution.

I don't see why Leo Fenders design beliefs can't be translated to cars. "A quality instrument can be easily repaired."

My favourite cars so far have been the ones that have been cheap and easy to fix. A well designed car, can be easily repaired (or serviced).



Or could it possibly be that withholding procedure information, and making repair work tedious happens to be sickeningly profitable? No way, it's to protect the batteries that hardly last 3 years even when they're away from all that heat. 🤣

Two big design influencers are:
1) Chasing fuel economy
2) Reducing crash damage/rollover propensities

Some influenced-design examples:
The IBS is intended to manage electrical/electronic power/alternator use, thus minimizing related fuel consumption. Putting multiple electrical/electronic systems on the same wires not only saves copper material but also saves weight, thus also increasing fuel economy. Locating battery below floor, thus lowering center of gravity, thus reduces rollover propensity.

Sadly, the increased complexity is often met with shortcuts taken by "some" technicians. Some of the shortcuts damage the vehicle. Some of the shortcuts consist of not performing the subject service and claiming that the service was performed! My then-girlfriend, before she married me, insisted on "dealer-recommended" service for her Acura. One time I took her to pick up the serviced car and I checked, among other things, the translucent master cylinder reservoir; the service was to have included a full brake system flush. Guess what, the master cylinder showed quite-brown fluid; the tech perhaps was used to customers not checking/not knowing what to look for, and claimed it was an unintentional "oversight"!!! I made sure to notify the Service Manager (of course they quickly remedied the "oversight") and the dealership management, and I related the experience in some online ratings.

I've been quite impressed with known-name-brand AGM (Absorbed Glass Mat) type batteries like the one used in my particular Jeep. They are called on to do a lot; I have found them to be resilient, and to not require much maintenance.

 

[Bob Lincoln]

There are at least two benefits from getting the battery out of the engine compartment:
1) Better weight distribution.
2) Battery is not subjected to engine heat and can have a longer life.

And with our Chrysler 200 cars, my wife's battery was still good at 7 1/2 years. I replaced it proactively. Mine (used car) still had the original battery when it failed at the 8 year mark. The battery is mounted in the left front wheelwell, away from engine heat. Yes, not so easy to change; but how often do you have to touch it, when it lasts so long?
There you have two OEM batteries that were away from heat and lasted a LONG time.

 

[Bob Lincoln]

At the risk of being banned by the site police, I'll just ask the follow-up question, "What external factors push the engineers to design cars to be so complex and expensive?"

As an engineer, I can tell you - management. Engineers know what to do, how to make things serviceable and simpler. Management gives the orders, however. And you either comply or are replaced. It takes a LOT to make a case to overturn some of these decisions.

 

[d150le]

Have you had a car with a battery under the seat or inside the car or are you just complaining?

I think we've done this dance before where I state my opinion on something and you dislike it and assune it's complaining.

Additionally, I don't believe it is a rule of law nor the forums that you have to own something to be eligible to speak your opinion on any given topic. That would encroach upon that freedom of speech we see you guys south of the border defending so often.

However, I'll answer your question with yes. I owned an LX. I was unbelievably lucky in that whoever actually built that battery, and whoever sourced the batteries for the cars at the time did a fantastic job. However when it was time to replace it, beding over the truck triggered a sciatic episode for me. Never once had that happen while swapping batteries from inside an engine bay 🤣. I got 9 years off that original battery. I also got 8 years from a couple other batteries which were located in the engine bay.

Really sorry you have such a hard time disagreeing with people, I do have respect for your knowledge of Mopar.

Fully understand they're designing cars to save space and assembly time, but lets not pretend they're not also doing it to make money on service and/or making cars too expensive to repair vs buying a "better" new one.

 

[Bob Lincoln]

Let's not pretend that they are - because they're not. That's not how engineers operate. We are mandated to do cost reductions continually, but they don't involve making things less rugged or harder to service. No one has, or is allowed time, to reduce quality and test to see if it met a reduced life goal. Doesn't happen. I speak from over 40 years in engineering at large international companies.