2013 Q5 trailer wiring
#1
08-26-2013, 09:47 AM
2013 Q5 trailer wiring
Called the dealer and they want $2300.00 for complete install. Etrailer has a hitch for a couple hundred, but I am not sure about the lights wiring. Audi says they must install some module and it cost just as much as installing the hitch.
#3
12-07-2013, 06:01 PM
Your dealer is high, very high. I don't know if the "module" is already in the car, or part of the Audi option kit, but the Audi hitch is welded onto a replacement for the rear bumper frame, it is not just bolted on the way all the aftermarket ones are. Also, the dealer changes the ECU program and the car is supposed to shift differently under load, and cool the engine differently, among other things. They're a little vague but the car gets "recoded" when the dealer installs the hitch.
If Etrailer or UHaul says they have a complete package I'd believe it, they should have the experience to make it work. But IIRC U-Haul usually does 4-wire connectors and the Audi is a new 7-wire, and U-Haul shops sometimes splice in instead of using harness connections in the car. Compare carefully, but check another dealer for the price. "Really, I'd love to give you my business, but that price is way higher than the competition..."
And I'd bet any VW dealer would be happy to do the job as well, if they can do the coding.
If Etrailer or UHaul says they have a complete package I'd believe it, they should have the experience to make it work. But IIRC U-Haul usually does 4-wire connectors and the Audi is a new 7-wire, and U-Haul shops sometimes splice in instead of using harness connections in the car. Compare carefully, but check another dealer for the price. "Really, I'd love to give you my business, but that price is way higher than the competition..."
And I'd bet any VW dealer would be happy to do the job as well, if they can do the coding.
#4
12-12-2013, 05:38 PM
We sell the Q5 hitch for 690.06, plus the bracket to hold the module for 40.30 dollars. Most cars require the holder. The contents of the kit include the hitch, the wiring for the hitch, and the 7 pin connector with the spring loaded cover. Then you can buy the adapter to go to a 4 pin which many trailers use. Labor to install the hitch takes about 4 hours. At 122.00 an hour this should total up to 1283.00 if your dealer is charging retail on the hitch and using the same labor guide as we do here. You should call around and see if what other dealers charge. Call one from outside your state just to compare.
The hitch is not welded on, it's bolted in place. The problem you face if you put on a non Audi hitch is with the trailer lights and the trailer brakes if equipped. The tail lights on the Q5 use pulse modulation. The center LED section is lit up when the tail lights are on. When you use the turn signal that same center section modulates/pulses. For this reason, the module is needed for the trailer hitch for a couple of reasons. Since you can't cut into the wiring to find what we (me included) used to look for, a brake light wire and a turn signal wire, those don't exist any longer with this pulse modulation system. (in rethinking how this must work I realize the module must have a wire that tells it what to do. Fed to it through the brake light switch system, and then the turn signal switch system. But knowing where to exactly tap into that given the complexity of the system would be a hurdle for most people). The module sends that signal to the 7 pin connector. The module also deactivates the rear view camera. Otherwise it would see the trailer all the time and probably chime continuously. As somebody else said, it also feeds signals to the rest of the car so among other things the ABS and suspension now know it's towing a trailer. Much in the same way the roof rack knows when the transport bar is installed, the suspension reacts differently. You guys are way more tow savvy than I am, but I'm thinking:what use is a hitch without the module? That every trailer big or small has to have lights, which makes any aftermarket hitch without a module worthless.
I did try to run the part numbers for the module and the wiring harness used on the hitch and they are not recognized. Meaning the only way to get them is to buy the Audi OEM hitch kit. In Audi's defense, you could look at it like the hitch is well priced at 250.00+the module at 300.00 (and there aren't many inexpensive cpu or modules on any late model car now-a-days)+the hitch wiring harness at 140.00 makes the 690.00 price a little easier to swallow? Then again I'm not the one buying it, so I understand that.
The hitch is not welded on, it's bolted in place. The problem you face if you put on a non Audi hitch is with the trailer lights and the trailer brakes if equipped. The tail lights on the Q5 use pulse modulation. The center LED section is lit up when the tail lights are on. When you use the turn signal that same center section modulates/pulses. For this reason, the module is needed for the trailer hitch for a couple of reasons. Since you can't cut into the wiring to find what we (me included) used to look for, a brake light wire and a turn signal wire, those don't exist any longer with this pulse modulation system. (in rethinking how this must work I realize the module must have a wire that tells it what to do. Fed to it through the brake light switch system, and then the turn signal switch system. But knowing where to exactly tap into that given the complexity of the system would be a hurdle for most people). The module sends that signal to the 7 pin connector. The module also deactivates the rear view camera. Otherwise it would see the trailer all the time and probably chime continuously. As somebody else said, it also feeds signals to the rest of the car so among other things the ABS and suspension now know it's towing a trailer. Much in the same way the roof rack knows when the transport bar is installed, the suspension reacts differently. You guys are way more tow savvy than I am, but I'm thinking:what use is a hitch without the module? That every trailer big or small has to have lights, which makes any aftermarket hitch without a module worthless.
I did try to run the part numbers for the module and the wiring harness used on the hitch and they are not recognized. Meaning the only way to get them is to buy the Audi OEM hitch kit. In Audi's defense, you could look at it like the hitch is well priced at 250.00+the module at 300.00 (and there aren't many inexpensive cpu or modules on any late model car now-a-days)+the hitch wiring harness at 140.00 makes the 690.00 price a little easier to swallow? Then again I'm not the one buying it, so I understand that.
#5
12-13-2013, 10:31 AM
Jeff, thank you for the details. Any idea why Audi deletes the towing eye screw points on the hitch's cross-bar?
There are many reasons to have a hitch receiver installed without pulling a trailer, i.e. a bicycle rack or scooter/wheelchair carrier, either less than 200# loaded and not using any lights or wiring. Although personally I'd do it all up at once, rather than skip the wiring.
From the sparky point of view, signaling the ABS and ESC about extra weight is almost irrelevant unless the module can actually weigh a trailer and signal how much the extra load is. As it is now, if it does signal changes, it is saying that a 100# unloaded bike rack is the same as a 4000# loaded trailer--which is worse than no signal at all.
Cars with LED lighting systems are notorious for having problems when the power drain (electrical load) on them is changed. So I would guess the main purpose of the module is really that of an interface box, using power transistors or optoisolators to make sure that any "extra" lights do not pull down the load on the normal lighting circuits. That's fairly simple and common electrical design, to use isolators that way. And fairly cheap as well. The ABS/ESC signaling? More of a bonus than a necessity.
And then of course there's the "reprogramming", supposedly the alternator and cooling systems and transmission will now be told "there might be an extra load" and adapt to it, as opposed to the industry standard of oversizing them with different stock components?
I'm left with the feeling that some ex-Porsche engineer was told "You will make a trailer hitch, our customers keep asking for one." and for some time afterwards, said engineer lay on the floor kicking and screaming "Nein! Nein! Nein!" and then swearing petty vengeance when he was compelled to make it happen.
The engineers I know, would have included a new pre-cut diffuser panel in the trailer kit and finished the job off nicely.
There are many reasons to have a hitch receiver installed without pulling a trailer, i.e. a bicycle rack or scooter/wheelchair carrier, either less than 200# loaded and not using any lights or wiring. Although personally I'd do it all up at once, rather than skip the wiring.
From the sparky point of view, signaling the ABS and ESC about extra weight is almost irrelevant unless the module can actually weigh a trailer and signal how much the extra load is. As it is now, if it does signal changes, it is saying that a 100# unloaded bike rack is the same as a 4000# loaded trailer--which is worse than no signal at all.
Cars with LED lighting systems are notorious for having problems when the power drain (electrical load) on them is changed. So I would guess the main purpose of the module is really that of an interface box, using power transistors or optoisolators to make sure that any "extra" lights do not pull down the load on the normal lighting circuits. That's fairly simple and common electrical design, to use isolators that way. And fairly cheap as well. The ABS/ESC signaling? More of a bonus than a necessity.
And then of course there's the "reprogramming", supposedly the alternator and cooling systems and transmission will now be told "there might be an extra load" and adapt to it, as opposed to the industry standard of oversizing them with different stock components?
I'm left with the feeling that some ex-Porsche engineer was told "You will make a trailer hitch, our customers keep asking for one." and for some time afterwards, said engineer lay on the floor kicking and screaming "Nein! Nein! Nein!" and then swearing petty vengeance when he was compelled to make it happen.
The engineers I know, would have included a new pre-cut diffuser panel in the trailer kit and finished the job off nicely.
#8
12-18-2013, 07:41 AM
Apparently it is not just a matter of "wiring", but if you simply tap into the existing wiring the same way that you would tap into a 1970's Chevy....you'll drive the computers in the Audi mad. They may get outright hostile if they see substantial loads added to the factory lighting circuits, and that's what the expensive interface boxes are designed to prevent. Every interface box (assuming you can get them from third parties) should take care of the number of options (4 to 7) that it makes available at the plug end. Some companies are using the 7-pin connectors, as Audi does. Others are still just using the basic 4-wire.
#9
12-18-2013, 07:14 PM
Redd, Porsche engineer comment, good stuff there. In looking at the reinforcement that does come off the car and stays off, that threaded hole is outside of the mounting location for bumper reinforcement to chassis. And in the link below, in one of the pictures you can see that the hitch stops right where the mounting location is. Plus the tubing is round in shape. My guess is Audi figured if you were going to tow the car on a flatbed you would use the brackets on the hitch where the tow chains from the trailer would attach. In place of the factory towing eye for hitch equipped vehicles.
Audi Q5 Tow Hitch Installation – Audi Certified Service | I Am Audi
Audi Q5 Tow Hitch Installation – Audi Certified Service | I Am Audi
#10
12-19-2013, 11:36 AM
Jeff-
I suspect that the original mounting points were designed by engineers who said "We need a strong point..." and that got cast in stone, so to speak.
Then at some point, other engineers (or perhaps, salesmen<G>) said "We need a provision for a towing hitch" and that second team said "And what's the cheapest way to do this, and maximize profits? Gee, you know, we don't need those hard points any more, we can save $25 by omitting them. Whaddaya need hard points on the corners for anyway?"
And, as these things usually do, they got omitted because they could be.
I still find that contrary to the German tradition of letting the engineers design the product but I'm not about to take my old bumper cross member (whatever that is properly called) and weld a new hitch onto it. Not this year.<G>
Odd that Audi doesn't retain the old cross-member and cycle it back into the parts stream for crash repair parts, that's an expensive piece of metal and one commonly needed by repair shops. Obviously, not the same team that figured out how to save $25 by deleting the hard points from the new part!
I suspect that the original mounting points were designed by engineers who said "We need a strong point..." and that got cast in stone, so to speak.
Then at some point, other engineers (or perhaps, salesmen<G>) said "We need a provision for a towing hitch" and that second team said "And what's the cheapest way to do this, and maximize profits? Gee, you know, we don't need those hard points any more, we can save $25 by omitting them. Whaddaya need hard points on the corners for anyway?"
And, as these things usually do, they got omitted because they could be.
I still find that contrary to the German tradition of letting the engineers design the product but I'm not about to take my old bumper cross member (whatever that is properly called) and weld a new hitch onto it. Not this year.<G>
Odd that Audi doesn't retain the old cross-member and cycle it back into the parts stream for crash repair parts, that's an expensive piece of metal and one commonly needed by repair shops. Obviously, not the same team that figured out how to save $25 by deleting the hard points from the new part!
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