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Followup To
Question -
I have a 1998 Chrysler Sebring Convertible. I have a problem with the resistor for the heater/air conditioner. It keeps blowing the diode causing me to only have High fan.I am on my way to the dealers to get another new one. I've blown out 4 of these in the last 3 months, 3 of these where used ones the dealer recommended a new one well low and behold that died today, at least this next one will be free. Any ideas whats causing this? I asked the dealer but it's one of those you got to leave the car and at $72.00 an hor labor I don't want to pay a fortune for a $17.85 part. THANK YOU.
Answer -
Hi Michael,
That is an interesting history. Apparently there is too much current flowing through the resistor for it to handle. You might want to verify that the three resistors that are individually put in series with the diode resistor to get the various speeds are not of unreasonably low resistance value. One of them may be shorted and thus putting too much of a load on the diode resistor when you choose that particularl fan speed. If you can recall what speed you were using when it blew out that would be a clue.
Have you measured the resistance of the diode resistor, and how does it compare with the resistances of the three other resistors. I suspect there is no wattage value on any of these resistors, but I suppose the best thing would be to try to increase the heat dissipating capacity of this segment of the circuit by substituting two resistors (of half the resistance) but equal heat dissipating capacity to the stock part in series with oneanother, or two resistors (of double the resistance) but equal heat dissipating capacity in parallel to oneanonter. I have not heard the term "Diode" resistor heretofor. Does it appear to have a different resistance depending upon which polarity of the test meter leads you apply to it? If this is just a high heat dissipating capacity resistor I suspect you can just buy resistors from an electronics supply store for much less money.
So let me know what else you can tell me about the electronic details of the these components.
Roland
I was just told by the dealer that it was the blower motor causing the trouble. This part has just 1 diode the other coils don't have them. This resistor is right up next to yhe blower motor most chrysler productc stratus.cirrus etc are interchangable. Thank you once again.
AnswerHi Michael,
I don't have the wiring diagrams for the Sebring, but I do have the '96 Cirrus/Stratus shop manual. It shows there to be a "thermal limiter" and three resistors in the blower motor resistor block. Is that the diode resistor? It appears in that circuit that the 'tl' is in series with the three resistors and that the blower switch picks off the current after 1, 2, or three of the resistors have been brought into play, and grounds it, while on 'high' the tl and resistor chain are by-passed. I would still want to know if the resistor chain is up to spec. The other possibility is that the 'tl' needs to get plenty of cooling air passing over its surface to avoid meltdown. If you had another chain of resistors with which to compare ohm reading that would be worth doing. Otherwise you have to accept the dealer who is essentially saying there is something wrong with the blower motor. If you have an ammeter it might be worth the effort to see how much current the blower is drawing when on high.
You have caught my interest, please let me know what you learn.
Roland
