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A/C problem with my 1984 300DT
On rare occasions when I turn the A/C on and select high fan speed the blower is very fast (read powerful) and the temperature is very cold......Great! On other occasions in fact most of the time when the A/C temp is selected and the high speed fan switch is selected the fan is slow and the temperature is warm to cool. Yet at other times if I switch off the engine before switching off the A/C for example when refueling and then turn the engine back on the fan blows H-O-T. I've been told that the problem is cold solder joints in the A/C module and that I should remove the A/C module and resolder or at least reflow the joints. Does that sound right or could it be something else?
A/C problem with my 1984 300DT
Well, I have had intermittent A/C problems on occation, as well (1984 300 DT).
My semi-limited experience suggests the following:
First, make sure that the electical connection on the heater contol valve (engine upper center of firewall) is working properly. I pulled mine off the car and bench tested its opperation by applying 12 volts to the terminals. I think, this valve is normally OPEN in the resting position (which means hot water is flowing when no voltage is applied). Then, clean the terminals rear well (both the male and female side). Then, I would adjust the temperature control when it starts acting up (to see if this will have any effect on the system). You should hear the vacuum actuators working the vents. (is your vac system working ok?). Also, there may be a problem with the sensor on the dash (and the venting system that pulls the sample air thru it). Then, if you are still not getting results, you can open up the control module and look for bad solder joints (mine was fine, I put it back together and it has been working pretty well ever since). You might find someone to loan you a good one, to see if that fixes it....That's my 2 cents worth.
cory 352-978-1314 cell #