Category: Maintenance

Air only blows out the defroster – repair.

My Jeep had the typical problem where the HVAC only blows out the Defroster. The defroster is the default mode when there is no vacuum supply. So I set about finding my vacuum leak.

It did not take me long to find an obvious break in the plastic vacuum tubing. The trouble was, it was broken on the cabin side of the firewall. It was too far in to reach to make a splice.

Replacing leaking freon lines on my XJ Cherokee

After replacing my engine, I had to reconnect the AC lines and replace the freon. The system was originally designed to run R12 but I swapped over to R134 a long time ago. However, I still like to use my old gauge set on the R12 style fittings. I just adapted the yellow hose to fit the R134 cans.

I installed a new dryer and reconnected the hoses using new O rings where the old ones looked bad. I then hooked up my vacuum pump and pulled al the air out. I shut off the pump and closed the valve to see if it would hold. It held vacuum so I assumed no leaks and popped in the first can of freon.

They say if you don’t use something in a year you should get rid of it.  Well, I don’t take that advice on tools. I can’t remember how many years it’s been since I last used this tool but today it was really handy to have.

When I was trying to figure out the trouble with my Porsche tail lights I found that the previous owner had modified the wiring for the left side tail light.  Also, the front corner markers have never worked since I have had the car.

Tracing the circuit, I found a dead short in the left side wiring that would blow the fuse. I assume this is the reason why they have jumpered the tail light wires and disabled the front markers.

Using the above tool, I was able to trace the short to somewhere in the front fender area. Without it, I would have just been guessing.

I made a jumper to use the tool to put power to the load side of the fuse and took power straight off the battery. Since there was a dead short I did not want to stress the light switch while searching for the short.

I was able to use the little meter to follow the wire through the car and down into the fender. I then put the car on the lift and removed the belly pan to get access to the wire. Since there was just a short section of wire to inspect I decided to do a visual inspection instead of continuing with the tool.

It took some searching, but I finally found the problem.  The wires inside the left side marker were twisted together and the ground was touching the power lead inside the rubber cover.

I hooked them back up correctly and the short went away.  I then redid the wiring at the tail lights to put it back as the factory intended. now there is a fuse for the left and a fuse for the right. And another fuse for the tag lights.  Germans like fuses I guess.

Thanks goodness I had this handy Short Circuit finder tool.

Tracking down an intermittent electrical problem in my 1988 Renix Cherokee.

Trouble started a couple of years ago in Harlan when I lost one cylinder. I had five perfectly good running cylinders and one that simply did not fire.  After some experimentation, I found that swapping the injector wiring around would move the dead cylinder.  Tracing the wiring back under the dash led me to replace the ECU.

How to tighten up the steering box on a Jeep Cherokee XJ.

The Jeep Cherokee uses a Saginaw steering box like many other vehicles. You could swap in one from a Chevy or a Durango if you wanted to change the steering ratio. I prefer to just keep the stock one.

To access the adjuster screw, you have to remove the electric fan. You can get more space by removing the air box but that is not entirely necessary.

How to replace the muffler on an XJ Jeep Cherokee