Author: Mike

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1995 GMC Suburban HVAC controls repair

1995 GMC Suburban HVAC controls repair

The 1995 Chevrolet and GMC trucks are unique in their HVAC controls. Even though the appearance of the panel is similar, the 1994 and earlier use a different control head as well as the 1996 and later.

The mode selector switch and the temperature control switch operate electric actuators on their respective mechanical dampers. The controller sends a variable voltage signal to the actuator to command it to move to the appropriate position.

The fan speed is controlled by a separate multi position switch. The fan switch operates independently of the rest of the HVAC controls in the control head.

The mode damper control and temperature control is accomplished using transistors, diodes and resistors on a circuit board mounted behind the control knobs. Some people have reported success in replacing faulty transistors to get their controllers working again. I tried replacing the defective transistor on my board but it did not restore proper operation.

A complete replacement head unit is around $140 from Amazon.com. I was able to get one from a junkyard for a lot less. The circuit board is the same for the pickup, Tahoe and Suburban. The main difference between the different vehicles is the rear defrost control relay. The relay can be swapped into a base that does not have one.

To remove the controller from the dash, begin by removing the dash surround. Simply dig your fingers into the groove around the face panel and pull back to release the clips. To get enough to room to remove the panel, it helps to have the gear selector in low.

Before you can pull the panel very far out, you will have to disconnect the head light switch. Simply depress the locking tab and separate the plug. Set the panel aside.

The HVAC controller can now be pulled form the dash. However to get enough room to access the wires, you will likely have to remove the radio. It is held in place by two clips on the slides on each side. Depress the clips and pull the radio straight out. Disconnect the antenna cable first and then rotate the radio to disconnect the other three harnesses. Make sure that you have the theft lock code before depowering the radio, or turn the theft lock feature off.

Now you can pull out the HVAC control panel from the dash. It is likely that the locking tabs will break, as this plastic gets brittle with age. The locking tabs are not critical, as the front plate will hold the controller in place. Next, disconnect the two wiring harnesses. Mine were very difficult to separate form their sockets. There is more wire behind the dash that can be pulled out to get a better grip on the plugs to separate them.

Replace the defective components and reinstall the controller, radio and front panel.

The mode door actuator is located near the transmission tunnel on the driver’s side. It is held in place by two small screws and a tab. The screws on mine had 7/32 hex heads. The actuator can be removed and tested to see if the trouble is the actuator or the control unit in the dash. My actuator was fine and the trouble was with the head unit.

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Welding Safety – Fire from the gas tank

Welding Safety – Fire from the gas tank

My dad told me about a time when he was repairing a shock mount on his Chrysler. He used the company boom truck to lift the rear of the car to a comfortable working height.

After the completed the welding job he flipped the stinger back and accidentally contacted the gas tank on the car. He was quickly surrounded by flames dripping from the tank. The little hole in the tank continued to fuel the fire.

He simply reached his gloved hand up and stopped the flow of fuel with his finger. The flame went out but he was then stuck like the proverbial little Dutch boy with his finger blocking the flow.

Soon my Grandfather walked by and asked “What are you gong to do now boy?” Dad suggested that he would continue to hold his finger in place while someone got him a roofing screw with a rubber washer.

My grandfather soon returned with a screw, washer and a wrench. Dad plugged the hole with a screw and the rubber washer made a liquid tight seal. He says that plug was still in place when he sold the cars years later.

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Cairo, Il Flood and the Birds Point Levee blast

Cairo, Il Flood and the Birds Point Levee blast

One my way to and from Missouri this winter I passed through Cairo, IL. I found it an interesting little town. Actually, it seemed more of a ghost town.

There are huge ornate buildings that look as if the city was once prosperous and thriving. The fact that is sits at the intersection of two major US rivers, the Ohio and the Mississippi.

I did a bit of research and found that the town was expected to surpass Chicago in size and importance. It once had as many as 30,000 citizens and now has less than 2,000.

Normally on my route to Missouri, I only pass near Cairo and not through it. However on my most recent trip the bridge across the Mississippi River was closed. I found it interesting that there were no early warning signs, Just barricades at the entrance to the bridge. The UPS truck in front of me was caught off guard as well. We both used the abandoned state park to turn around and search our maps for alternate routes.

The flood wall in Cairo has a huge gate over highway 3. I found it a bit creepy to drive through with the kudzu vines hanging down over the road and the huge gate looming overhead.

I had not thought much about Cairo until I saw on the news that thousands of acres of Missouri farmland were to be flooded to save Cairo. At first, I was like many who wondered if Cairo was worth saving. However there are some very interesting looking historic buildings there. But as I thought more and looked at the map, the levee at Cairo not only protects the little ghost town but many small towns and communities in the area.

Also, I learned that the Birds Point Levee was designed as a fuse in the flood protections system. There is a second levee one mile behind it that protects the actually populated area. The area between the levees is the New Madrid flood way. It is designed to carry excess water during times of epic floods like his one. The Birds Point levee was built with holes in it so that it could be easily blown up to open the flood gate.

The fact that farmers have been allowed to use the area during times of no flood has made it seem inconvenient to blow the levee. However, that was the design all along. The farmers knew the risk and most have put only portable and easily movable supplies there. However since it has been a very long time since the floodway was used, some have become complacent.

The Corps of Engineers has decided that blowing the Birds Point Levee was the best way to protect not just Cairo, but the entire levee flood control system. Nature is a powerful force when it goes to reclaim its own from our developments. I think we tend to forget that between the so called natural disasters.

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How to replace the hood release cable on a Jeep Cherokee

How to replace the hood release cable on a Jeep Cherokee

The Jeep Cherokee hood release is operated by a cable that connects the release mechanism on the hood to the handle on the kick panel. As the cable ages, it can become hard to pull and can eventually fray. If the cable breaks or becomes disconnected from the hood release, it is almost impossible to open the hood without damage.

To remove the old cable, begin by opening the hood. Place a cloth or block over the hood latches to prevent them from catching should the hood be accidentally lowered during the procedure.

Use a flat blade screwdriver or other pry tool to pop the end of the cable sheath out of the release mechanism. You may need to pry the mechanism away from the hood to get clearance. Rotate the end of the cable so that it aligns with the slot and slip the end pin out. Again, you may have to pry the mechanism away from the hood to get clearance.

Remove the cable from the clips on the hood. Use a screwdriver to pop the rubber grommet through the firewall.

Move inside the Jeep and remove the kick panel trim. It slips under the door sill trim, but you may be able to slip it out by removing only the front two screws rather than removing the entire sill panel.

The release handle is held in place by three number three Phillips head screws. If you try to use a standard number two Phillips you may strip the screw heads. I used a number three bit in a socket with a quarter inch drive ratchet to remove the screws as they were very tight.

If you have made the doors removable, it is helpful to get them out of the way when doing this repair. If the screws are corroded, you can gain access through the hole for the door wires and spray penetrating oil on the back side of the bolts.

There is not a straight path to pull the cable out, so it may be helpful to have an assistant pull the cable through the firewall while the other guides the end of the cable through the hole. When replacing the cable, it is helpful to have an assistant push the cable up while the other catches the end with needle nose pliers or a screwdriver.

Work the grommet into place and seat it in the groove. Have an assistant press from the inside while the other is pulling from the outside to press the grommet into place.

Pull the new cable through and attach it to the release mechanism by slipping the pin in the slot. Clip the end of the cable into its slot. I used a pair of vise grips to pop it into place. Attach the cable to the clips on the hood.

Align the handle with the screw holes and install the three screws. Reinstall the kick panel cover and tighten the screws.

Test the release action several times before closing the hood. Make sure that the end of the cable is properly seated and does not pop loose. Once you are sure of the release action, close the hood. Enjoy your new hood release.

The hood cable is part number 55235483AD for 96 to 01 and 55026030 for 1987 to 1995. It cost about $20.

Update: Wayne Klotz adds these tips: I have seen some Cherokees with torx bolts holding the cable mount… Also when pulling the old cable through, attach a light rope and pull it thru the firewall. It is helpfull when pulling the new cable thru.

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Tornado Safety

Finding the safest place during a Tornado

As the storm moved into our area of Cleveland Tn and Bradley county, there was a lot of talk about tornado safety and the safest places to hide during a tornado. The weather men warned to stay away from windows and exterior walls. They warned to stay out of cars and to seek shelter in underground areas and interior rooms like the bath room.

As I drove through the devastated areas to reach the house where I was helping clean up, I was amazed at the destructive power of the tornado. I have come to the conclusion that short of an underground storm shelter, there is no safe place to be when a tornado strikes.

I have often disagreed with the advice of not sheltering in a car. After all, cars are designed for high speed impacts. However, after seeing Bill Maxwell’s Lincoln, I have changed my mind. He told me that just a few minutes before the storm hit he had been sitting in his car listening to the weather reports. He lost reception so he had just made it to his bedroom when the tornado stuck his house.

His Lincoln Town Car, is now a ball of metal sitting in his pasture about a quarter of a mile from his house. The roof is crushed down to the level of the seat. I don’t think even a belted in occupant would have survived the tumbling and crushing of the car.

I still think my race car with a full cage might have fared better, but a normal car is definitely not a safe place. The repeated pounding of the tumbling action completely crushed the passenger compartment of the car.

Another part of a house that seems safe is the fireplace. After all the brick structure is often seen standing long after the rest of a house has rotted away. However, at Bill’s house, the fireplace was cleaned to the concrete base by the winds and parts of the brick chimney were strewn all through the pasture.

Yet another place that people often find shelter in a storm in inside a bathtub. While there have been numerous reports of people riding out the storm in their bathtubs, Bill’s bath tub was found a couple of hundred yards away from his house. I don’t think that would have been a safe ride either.

Bill was in his bedroom when the storm ripped his house apart around him. The four walls of the bedroom were the only thing left standing at his house. He told me he climbed out form where the exterior wall had separated form the foundation. He was greeted there by his dog.

He said he did not know where the dog was during the storm, but he had somehow found a safe place. Based on what I saw while cleaning up the damage at Bill’s house, the only safe place to be is where you are. Apparently if you are protected from damage, you will be safe where ever you are. I think it was Bill’s attitude that protected him more than any of the building parts.