Jeep GC 95 Climate Control Code Problem

dmccall did pass the time by typing:

ER=error, the AC system has thrown an error code.

On the manual version that is caused by a blown resistor pack, but on the automatic system it's a power module and relay combination that is located by the blower motor. (don't remember exactly where, but if you follow the blower wires you will find it.) The power module controls lower speeds and the relay runs the high speed. So if it's on high then your relay is ok, but the power module is probably toast.

When the ER pops up, press either A/C or Recirc and the codes should scroll by.

I've got some data on the earlier system but nothing specific for your year. 93 should be the same as 95 for the ATC system.

DougW proclaimed:

On the '95 If you don't see codes by pressing either A/C or RECIRC, [you will also see the little stickman if that works] go to diag mode.

Press both A/C and RECIRC and hold down. Turn the ATC knob one click clockwise. All the segments in the display come on.

Let go of A/C and RECIRC and you should see 00 in the display with no stickman.

Push either A/C or RECIRC once. You should see the stickman again. Write down the fault codes you see at this point. 25 or 29 means the ATC module is toast and the rest of the codes may be gibberish.

From there, you can check a few of the major circuits. Just turn the ATC knob until you see a number, then push the A/C button and record the value displayed. Caution, the tests are mixed with read input value and test output circuit all jumbled together.

Test I/O Subsystem Values

01 In Blower A/D OC, SC, or 00-255 or ? 02 In Blower Feedback ? or 00-255 03 Out 00-255 sets blower speed 04 Out Blower High 00=off 01= set blower high relay on.

Those would be the main ones. My guess is similar to Doug's, the blower control is toast. The relay is enough to get high speed only. If you ever smelled magic smoke, the controller probably shorted out, otherwise is either open or the input from the ATC panel isn't getting to it.

Lon did pass the time by typing:

Interesting, that is the same procedure in my book for the 93

Guess the system didn't change much till 96.

Hi there,

So many thanks for the help so far. Much appreciated.

So I did the steps suggested. When I get to diagnostic mode, and hit a/c once I get the code 48.

Then turning the ATC knob hitting the a/c button, and doing this 10 times from numbers 1 - 10, gave me the following results

1 - 89 2 - 00 3 - 00 4 - 00 5 - 44 6 - 95 7 - 12 8 - 42 9 - 00 10 - 94

Clearly I need to invest in an after market manual.

But in the meantime any additional comments on what your thinking is given those codes, would be great.

Many thanks again Duncan

snipped-for-privacy@gmail.com proclaimed:

Blower fan feedback circuit

may want to twiddle with this one to see if your issue is the control module or the feedback.

Get the Factory Service Manual from

aftermarket manuals aren't even thick enough to use as monitor stands.

You might look around the blower motor for crudded up wiring. You'd want the factory manual before opening up anything in the dash to get at the control module.

Hi there,

Thought I would post a conclusion / follow up to this since I got it fixed.

firstly thanks for the help.

It was a blown blower resistor block, picked one up from a jeep dealership (not cheap!) and just replaced the old one under the passenger side foot well - nice easy fix! Works perfectly and the jeep is ready for summer and heading towards 250K miles!

Thanks again

I think I would want to know WHY the resistor block opened. If you didn't fix the cause, it may happen again, and soon.

Dick