Radio clock display and horn don't work

I haven't been able to find anyone who can help me with this. ..my clock
display on my 2001 PT (limited edition) goes out from time to time. The
radio continues to work properly and when the display comes back on, the
time is correct it just doesn't display all the time. I've had the radio
replaced and still the same problem. I've also discovered that when the
clock isn't displaying, the horn also doesn't work. Hmmmm. We've had the
service guys check it out twice but they won't address the correlation
between the two functions. They want to change out the horn...since
changing the radio didn't work, I don't have much faith the horn change
will do anything other than cost me money. I've checked the fuses and
they all operate correctly. When the clock is displaying and the radio
fuse is removed, the horn continues to work. The only time the horn
doesn't work is when the clock is not displaying. It seems to me that
there is a shared power connection between the two functions that is loose
somewhere. Any idea where

 

There are 3 fuses that control the radio. fuse 18, fuse 13 and fuse 2. fuse
14 is for the radio. they do not share the same fuses or the same ground.
if the only thing that goes out in the radio is the clock or the clock
display and the rest of the radio works your problem is in the radio and
more then likely the horn is a seperate issue. Thats my opinion without
seeing the vehicle. who replaced the radio? Dealer?. I will not be here
after Friday to reply back. I will be back a week after.

Glenn Beasley
Chrysler Tech

 

From what you say I would reach that same conclusion.

I've solved similar problems by spending a few hours pouring over the
wiring diagrams in my maintenance manual.

 

Dealer did the radio change and problem still persists. There is definetly
a shared connection between the horn and radio display.I have watched this
event for months to have come to this conclusion.I wish I had the talent to
understand the wiring system on the repair manual.

 

I agree that the two are connected since they always occur together.

The only feasible way to get it troubleshot is to find someone who can
read the schematics and has some troubleshooting skills. If I had
access to the PT schematics, I'd take a look, but I don't.

The LH cars have the power amplifier and horn relay powered by the same
fuse - obviously not the same vehicle, but not surprising if the same
power system design philosophy was used - definitely worth a check.

If it's not a common wiring issue, then a module - probably BCM is bad
or in need of re-flashing.

Have you tried disconnecting battery to reset the BCM?

***If my hunch about common power to the amplifier and horn relay is
correct, that's the most likely cause.***

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Hi...

Not a mechanic, just an old long retired electrical guy, but
a thought if I may?

Don't know PT's; never ever even ridden in one, but...

I'm wondering if the commonality here might not be the
theft protection system? If I "steal" or tamper with the
radio, does it or does it not cause the horn to sound
intermittently?

If so, it will surely be using a relay to do so, and that
relay will be interrupting the regular horn circuit.

If I were to bet on the solution, I'd be willing to bet
a dollar to a donut on the radio being the problem.
Seeing as the radio's been replaced, I'd be looking at
the radio wiring. I suspect I'd even invest a few minutes
in unplugging the radio connectors, spray a little contact
cleaner on the blades, and plugging/unplugging them several
times to clean them up a bit.

Just my two cents.

Take care.

Ken

 

Definitely worth considering.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

I thank you guys so much for sharing my pains.
During the weekend, I did a little bit of fiddling with the car,trying to
trace the connection between the horn and radio and in the process I
stumbled partially into the cause of the problem.
I disengaged the steering coloum lever and moved steering up and down to
view cable and discovered that with each movement, the display on the
radio comes on and off.I selected a position that kept the display on and
found the horn was also working and has been working since then.The
problem is definetely a partial contact at the the steering neck. The
problem is still there and I suppose that I have a temporal reprieve since
I could not identify which cables are responsible for this.

 

Does your PT by chance have radio controls in the steering wheel? If
so, one common thread may be the controls return wire for the horn and
radio thru the clockspring.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')