Is the problem the trailer hitch wiring?

[OITW]

I have a car problem I didn't use to have, and since most all of you have forgotten more about cars than I've ever learned, I've come to you for help. For starters, my car is a 2004 PT Cruiser turbo edition, what was their "loaded" model that year.

Following advice here, I chose to go with a trailer vice buying a pickup truck. I went with a local hitch installer who came recommended by local trailer places. The problems began even before the car came off the lift. With his tester plugged in, the left turn signal blinked rapidly which he said was a voltage problem I needed to have fixed, and the right brake light was out.

From the moment I drove away the turn signal has worked perfectly. Being forgetful, it was a while until I got the brake light, but when I pulled the old bulb it looked perfect. I put in a new bulb, and the light still didn't work. No apparent problem with the connector, but I didn't test it in any way.

Over the past week it's gotten worse. I visited with a friend and when I dropped him off I turned the engine off but left the car lights on. In about ten minutes I lost so much charge that the starter would fast click, but wouldn't start. I got a jump, immediate start. Two days later I got a battery light after starting the car, but it started fine.

I took it to Uhaul (the local manager there is great, regardless of corporate reputation, I should have taken it there in the first place), he used his tester and everything checked out, but said it sounded like something likely was wrong with the harness. I talked with another guy there for about fifteen minutes, then went back to start the car. Fast click no start. Nothing had been on, only on/off while we tested everything. Manager jumped me with one of those handheld chargers, instant start.

Got up yesterday morning to take my children to an appointment, fast click again. Luckily my neighbor was just leaving and gave me a jump. I drove about three miles to the appointment, parked the car commando in case I needed a jump to leave--and I did!

Returning, I stopped at the autoparts store to get the battery tested. The kid siad the voltage was good, but it was down to 200 amps or so. I do not understand how a battery can take a full charge but not generate sufficient amperage to start. He said the battery was four years old, and that even if I trickle-charged it to full it wouldn't start reliably. I started it there and drove home.

At home I disconnected the trailer harness from the positive post of the battery and electric taped the lead. I then attached a charger which started at 3 amps but quickly went down to 2 amps. I tested the brakes to see if I got my brake light back, but the right brake light was still out. However, after brake testing the charger indicated 3 amps again, taking a few minutes to settle back down to about 2 amps. I repeated the brake test to see what the charger did, it went up to 3 amps and dropped back to 2.

I left the charger on for about four hours, it was showing just above 1 amp when I disconnected it. I had no trouble starting the car to go the grocery yesterday evening, nor starting it to come home. I just started it again to test, no problems.

Does anybody have any idea what the heck is going on and what I should do? I've decided on taking the car back to the installer and asking him to carefully go over the wiring installation, but the more guidance I can provide the better I would feel about it. And if I'm missing the obvious, please tell me, you can't hurt my feelings.

Thanks.

[synergy]

First of all. We need to determine if you have a high parasitic draw on your battery.

The best way to check this is to get a multimeter and put it inline on the ground side of your battery with everything turned off.
like this video shows.

https://www.youtube.com/watch?v=zdIKNnwEjIs

Next. Im just guessing here but most likely he put the battery into something like a Vat 40 battery tester. Those are very precise and can measure a batteries real power. Voltage is meaningless in this situation its all about the CCAs cold cranking amps.

If you find you have high draw I would remove the trailer extension and retest. If it changes your results you know its the trailer wiring. If it doesnt change then most likely its your trucks wiring.

If it shows low draw then get your battery replaced and if your still having issues look into your charging system voltage regulator and alternator.

good luck!

[oil pan 4]

The battery problem is likely unrelated. When batteries get about 4 years old, they can quit with out warning. This is what happened to my last battery. It was working fine, luck for me it was a Saturday and didn't have to work, I came home from grocery shopping, then was going to go some where else an hour or 2 later, no start and the battery wouldn't take a charge.
The battery was starting the car perfectly before that, no warning what so ever it was getting weak.
Some batteries die a long slow death giving plenty of warning before their demise, other times they almost completely fail with no prior warning.

I bet they pulled the wiring harness till something broke trying to get some slack so they could cut into it.
Unless you are really good with vehicle electrical wiring it needs to go to the dealership.

The place and people who did your trailer wire install were likely highly rated because they kept all the most popular harness adaptors in stock, stuck them on and everything always worked as advertised. Then when they had to actually do something original, that required thinking and a little creativity such as custom wire in a P/T trailer hitch they were lost.

See if the bulb socket has continuity to ground.
This is the most likely scenario I can think of off the top of my head where the tail light wouldn't work but the trailer plug would test good. If I read your post correctly.

Also what kind of trailer connector did they install for you?
Is it a "flat 4"?