NAV display locks when car is hot

aziegler · #1 01-22-2007, 11:41 PM

I have a 2003 M5 with MKIV NAV. Works fine most of the time. Locks up, but buttons work. ie radio stations, scan search etc. Just no display. When it does lock up, the unitl will perform a reset after about 5-10minuets of being locked.

At times, when locking up, the map screen may update occasionally. When this happens the general travel direction is correct, but it shows me somewhere parallel to my current route. Acts like it is not correctly interpreting the satellites.

More troubleshooting revealed that this situation always happens when the surface of the car gets hot from the sun. Everything is fine in the morning when i pull out of the garage. And if it is a cold, overcast day, like in December, i never have a problem. I noticed that the NAV unit is extremely hot on a sunny day. the black surface of the car, and the NAV's mounting bracket in the trunk, are very, very hot. I suspected a problem with the NAV/DVD unit in the trunk. Until, one cold, but very sunny, day (if florida), the NAV/Map locked up. I ran back to the trunk, touched the NAV unit, and it was stone cold!!???

now i suspect the antenna. The dealer said they get a "receiver error". however because of what looks like water marks on the NAV unit, they refuse to repair it under warranty. I don't think it is the NAV unit.

Any thoughts?

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trapdoor · #2 01-23-2007, 01:24 PM

My Nav unit was the same - I had mine replaced under warranty as the fan had apparently failed. My unit also used to get roasting hot on sunny days.

I suggest you check the fan - is it ceased/clogged. You may be able to get a replacement. Why does your nav have watermarks on it? Has it got wet in the past?

aziegler · #3 01-23-2007, 03:31 PM

are you refering to the fan inside the NAV unit? if so, good thought. however, there has been 1 tiime the screen froze up and the NAV unit was cold. But the surface of the card was very hot.

I bought this car used. the dealer suspects that some body work may have been done and water gotten in at that time. since the dealer told me they would no longer cover the NAV unit. I opened it up to check for damage. I have done electronic repairs for 20+ yrs. all looked good to me.

X5Jay · #4 01-23-2007, 03:50 PM

Maybe the repeated heating of the trunk unit finally got to it and now shows up as random problems - even when the unit is cold.

So where are these water marks? That's a weird one. I'd press the dealer on it since it's still under warranty. Can you just clean the spots off and bring it to another dealer?

aziegler · #5 01-23-2007, 03:57 PM

water marks (if they are water marks) are on the top of the NAV chassi. just under mounting bracket. Now, since they told me this voided the warranty, i opened the unit, which now breaks the warranty sticker seal. no they say it is even more of a dead issue because i opened the unit.

it seems they dig for every excuse to not resolve a problem. i may still call customer service at BMW corporate.

trapdoor · #6 01-23-2007, 04:01 PM

Quote:

Originally Posted by aziegler

are you refering to the fan inside the NAV unit? if so, good thought. however, there has been 1 tiime the screen froze up and the NAV unit was cold. But the surface of the card was very hot.

I bought this car used. the dealer suspects that some body work may have been done and water gotten in at that time. since the dealer told me they would no longer cover the NAV unit. I opened it up to check for damage. I have done electronic repairs for 20+ yrs. all looked good to me.

Yes, the fan at the rear of the Navicomp. Also, are you running a genuine or copied Map disk? Mine was dreadful with a copied DVD - I wonder if the laser has to run at a higher power on copied discs (and therefore hotter)?

I don't think the Nav computers are as robust as we are led to believe. Problem now is that if you have opened it up and broken the tamper seal, a dealer definitely won't touch it.

aziegler · #7 01-23-2007, 11:19 PM

problem seems the same with original disk or copy. as for breaking the seal, this safeguard is to assure that the failure isn't caused by a stupid end user tinkering with the electronics and causing the problem. in my case the problem existed before i opened it. since BMW is aware of that, it shouldn't make a difference.

you are right about the NAV unit not being very robust. it is nothing more than a cheap DVD drive with a very simple (& small) computer main board in it. probably doesn't even cost them $100 to have manufactured. i can assure you they do not repair them!

thanks for all the input!!

KiwiJochen · #8 01-27-2007, 06:18 AM

I also have a MkIII that stops working when the outside ambient temp reaches >25 deg C. My car is dark blue.
The unit will stop reading the nav CD and sometimes freeze and crash.

I suspect my nav cooling fan is not working but I haven't removed it to test yet - too lazy :-)

jason325 · #9 01-28-2007, 01:55 PM

Just for anyones info reading this thread... I was using a copied DVD Map on very cheap media and got "CD/DVD Error" on very hot days while driving around the south of France in my dark blue E46 with MKIV Sat Nav... Basically it stopped working..

It turns out that was down to the no-name brand cheap media not liking the heat.. > 30 deg C outside.. and pretty warm in the boot/trunk! I used another brand and have had no further problems...

Obviously your unit though and not the DVD in this case....

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