PT Cruiser and trailer lights
 

It's my understanding the PT Cruiser (this is a 2001) requires a special
interface between the auto lighting and the trailer lights. If this is
correct can someone supply more information? (I suspect that hooking the
trailer brake/turn-sig lights directly to the auto "loads" the auto
lighting circuitry such that it won't function or even perhaps be damaged.
If this is the case I'd suspect the interface consists of a circuit that
appears as rather high impedance to the brake/turn-sig circuitry and
switches current from the tail lighting source to the brake/turn sig
lights when used (?))

Looks like I jumped the gun. With a little research, and looking at the
rear lights, it looks like the brake and turn-sig are separate bulbs--ie
they don't use the same filament for brake and turn-sig like a lot of cars
do. An interface module should only essentially consist of a pair of
diodes each side to drive the single filament on the trailer from
either/both brake and turn-sig circuits while keeping them separate in the
Cruiser.

jimhigh66 wrote:
> Looks like I jumped the gun. With a little research, and looking at the
> rear lights, it looks like the brake and turn-sig are separate bulbs--ie
> they don't use the same filament for brake and turn-sig like a lot of cars
> do. An interface module should only essentially consist of a pair of
> diodes each side to drive the single filament on the trailer from
> either/both brake and turn-sig circuits while keeping them separate in the
> Cruiser.

If what you say is the case, it's not just a pair of diodes - but there
is a converter box available to make it work properly. If you think
about it, a pair of diodes wouldn't help - you still wouldn't get turn
signal action while the brake lights were on. You could accomplish
what you need to do by adding a relay to cut out the brake light on
each side and hold it off for a second or two while the directional is
active on that side (in addition to your diodes) if you really wanted
to cobble something together yourself.

good luck,

nate

On Wed, 20 Jul 2005, jimhigh66 wrote:

> it looks like the brake and turn-sig are separate bulbs--ie they don't
> use the same filament for brake and turn-sig like a lot of cars do. An
> interface module should only essentially consist of a pair of diodes
> each side to drive the single filament on the trailer from either/both
> brake and turn-sig circuits while keeping them separate in the Cruiser.

That's what the "light converter/interface" units for sale at every U-Haul
location do, yes.

I've seen so many of these working improperly on the road. They seem to
have the standard 50/50 durability thing going (50 miles or 50 minutes,
whichever occurs first).

If I were pulling a trailer with a vehicle that had separate brake and
turn lights, I'd just add separate turn lights to the trailer and avoid
messing with Rube Goldberg "converter" devices.

"Daniel J. Stern" > wrote in message
.umich.edu...
> On Wed, 20 Jul 2005, jimhigh66 wrote:
>
> > it looks like the brake and turn-sig are separate bulbs--ie they don't
> > use the same filament for brake and turn-sig like a lot of cars do. An
> > interface module should only essentially consist of a pair of diodes
> > each side to drive the single filament on the trailer from either/both
> > brake and turn-sig circuits while keeping them separate in the Cruiser.
>
> That's what the "light converter/interface" units for sale at every U-Haul
> location do, yes.
>
> I've seen so many of these working improperly on the road. They seem to
> have the standard 50/50 durability thing going (50 miles or 50 minutes,
> whichever occurs first).
>
> If I were pulling a trailer with a vehicle that had separate brake and
> turn lights, I'd just add separate turn lights to the trailer and avoid
> messing with Rube Goldberg "converter" devices.

I went to the dealer and bought the MOPAR harness, complete with "converter"
for my 1999 Intrepid. Except for the LARGE hole I had to drill behind the
right taillight, it was a slick install - plug and play. Still going strong
and working fine 6 years and 100K miles later. It was a bit of coin (~$70
CDN), but comparable in price to the "plug-and-play" Reese units sold by the
local parts stores. Makes for a well sealed, robust installation.

Two notes:
The "converter" isolates the BCM which controls the signals from the trailer
lights - common trailer shorts don't roast your BCM.
Also, the common method of testing the turn/brake lights by turning on the
hazards and checking the bulbs doesn't do the trick any more - you need to
also have someone check to see that the brake lights come on when you step
on them in the car - to make sure the "converter" is still working properly.

--
Jeff Falkiner
95 neon - the Road Rocket
99 Intrepid - the Green Monster
04 Sebring - the Silver Bullet

Just put a new set of trailer lights on and could not find a set anywhere
that sported amber turn segments. I assume this is a common item in the rest
of the world.

Richard.

Richard wrote:
> Just put a new set of trailer lights on and could not find a set anywhere
> that sported amber turn segments. I assume this is a common item in the rest
> of the world.
>
> Richard.

just buy separate amber lights, no big deal.

nate

On Thu, 21 Jul 2005, it was written:

> Just put a new set of trailer lights on and could not find a set
> anywhere that sported amber turn segments. I assume this is a common
> item in the rest of the world.

www.truck-lite.com
www.pmlights.com

On Thu, 21 Jul 2005, "Richard" > wrote:

> Just put a new set of trailer lights on and could not find a set
> anywhere that sported amber turn segments. I assume this is a common
> item in the rest of the world.

Options from Truck-Lite:
http://tinyurl.com/by4ln

Options from Hella Germany:
2SD 964 169-111
photo: http://dastern.torque.net/lampics/2SD964169111.jpg
dimensions: http://dastern.torque.net/lampics/2SD964169111dim.jpg

2XL 005 194-011 (left; right unit is -021):
photo: http://dastern.torque.net/lampics/2XL005194011.jpg
dimensions: http://dastern.torque.net/lampics/2XL005194011dim.jpg

Options from Hella Australia:
http://db.hella.com.au/cgi-bin/catal...w&flmaint=2133
(the compact option)

http://db.hella.com.au/cgi-bin/catal...w&flmaint=1181
(the "go big or go home" option)

LEDs neatly sidestep the BCM interface problem; they draw next to zero
current; the BCM simply disregards the trivial extra current as normal
bulb-to-bulb production variations...also, no bulb burnouts, much less
problem with connections and grounds, etc, plus much better photometric
performance than is obtained from most US bulb-type trailer lights.

All this stuff is easily available; you just have to know whom to ask.

DS ;-)

Thanks for the comments. Nate is correct -- just a pair of diodes (an OR
circuit) would prevent turn flashing when the brakes are applied. And, I
certainly don't want to risk damaging the PT circuitry by possibly drawing
too much current. Nor do I want to rewire the trailer lights and make the
4-wire connection "obsolete" because I have other vehicles that have the
4-wire connection. It looks like it's not as cheap and easy as I first
thought.