Dodge Repair: Electrical gremlins: 99 Durango


Question
QUESTION: I have a 1999 Dodge Durango SLT, 2WD, 5.2 Engine. w/approximately 135k miles.I am having a weird set of electrical problems. Let me kind of explain this in reverse. I live in S Fl. where the temp is now rapidly approaching summertime. In the evening when I leave work at 10PM upon approaching my Durango I click the remote to open. (The same conditions exist if the door is manually unlocked with the key).It does not unlock; the interior lights do not come on; but the HVAC module lights up  with the light switch off and engine not running; door still open. The manual door lock/unlock switch on the drivers door is likewise not functional. Turning the light switch on causes the HVAC module to go dark (The HVAC is in the run w/o AC) as does starting the engine or closing the door and waiting for the CTM to time out. If the HVAC module is in the 'Off' position the only difference would be is that it would not be lit as all the other problems would still be existent. Driving would sometimes have the function come on intermittently for a short duration (The HVAC module in Run is dark when the blower etc. aren't functioning and dimly glows when the blower intermittently kicks in). Note: the AC compressor clutch is not functioning either when the HVAC module is in the AC mode. Now In the Early 7AM the remote keyless entry works; the doors unlock; the interior lights come on although ever since I first obtained this vehicle 11 months ago and the interior lights come on as just described, when the manual on/off switch on the dome light is pressed it causes that light to be brighter. The HVAC in run has the blower motor running. After starting and driving the auto door lock actuates but the AC compressor clutch is still not functioning. The blower speed switch is operating normally in all four positions. After about 1/4 to 1/2 mile I'm back to the conditions I described as at night. One other note; when the blower motor comes on intermittently it does so at a slower speed even though the switch position is in the highest but it still can be lowered by the switch. I have been reviewing the 1999 Durango Chrysler Service Manual with only more confusion. The wiring diagrams are difficult to follow. I have checked fuse and relays in the PDC, The CTM, the Fuse Junction Block. I don't want to have a dealer tell me a need a Blower Motor Which would also recommend replacing the evaporator, resistor, CTM, Junction Block, PCM or whatever without knowing the real problem. I feel as though there is some form of short, connecter, or wiring problem. I'm sorry for this becoming a novel but it has multiple symptoms and maybe needs multiple solutions. Thanks.

ANSWER: Hi Tom,
My closest Durango manual is for '04.
Without getting into individual circuit details, I would suggest that you start by checking the battery ground clamp/its wires/and the two ground wire attachment points (front of engine and near battery proper on the right side wall of the engine compartment). Similarly check the + cable clamp and wires at the battery for possible corrosion. It sounds like there is some sort of a weak connection such that the voltage is being degraded due to a poor connection on either post of the battery. I don't see any other explanation for the day/night dichotomy
May I ask what is the CTM?
To understand whether my '04 diagrams apply, does your engine compartment have both a power distribution center AND a power distribution module, nearby to one another?
Thanks for your understanding. Please read the PS (below) and respond to it.
Roland

---------- FOLLOW-UP ----------

QUESTION: Hi Roland: Thanks for your quick response. The CTM is the Central Timer Module which enables door lock/unlock, Turn Off/Time Out interior lighting etc. The '99 Durango has a Power Distribution Center with relays and fuses as well as a fuse/junction relay module. The CTM and Fuse Junction Module are inside the vehicle at opposite ends under the dash. If you're referring to the power distribution module as the Power Control Module PCM/Engine Control Module ECM which is the main engine computer they are located on opposite fenders in the engine compartment.
The day/night difference is in my belief an effect of ambient temperature, engine compartment temperature, as well as vehicle inside temperature possibly causing expansion/contraction of a component(s), connector, wiring or ground connection/grommets. I have to find some to trace this who will provide an honest explanation.
I am going to have a battery service performed including changing new cable connecters as a start.

Answer
Hi Tom,
It is now clear that the '04 diagrams are not entirely applicable to your '09.  It is possible though that the problem circuit is similar between the two years: specifically in the '04 the sentry key remote entry module and the HVAC control are powered by fuses 14 and 13 in the junction block in the cabin, respectively, and those two fuses are in turn both powered by a 30 amp fuse #28 in the power module box. If #28 may have a crack in its internal wire which is open/closed depending upon the local temperature. So check your '99 manual in sections 8-W-39 and 8-W-42 to see if you can find a similar dual purpose fuse that powers a pair of fuses (one for the remote keyless module the other for the HVAC control panel) and if so check that visually to see if it might have a cracked internal wire.
Otherwise, I can only suggest the cable connections I first suggested.
Roland
PS: As you look into your wiring diagrams, see if fuses #13 and 14 in the junction box (section 8W-12 of your manual) are possibly both powered by a 30 amp fuse in power distribution center box. If so, that would be the fuse that may be flakey. The wire that connects such larger fuse to the two smaller fuses MAY be labeled A918 for reference. That is what I am seeing in the '04 diagrams and as such a possible cause of your problem.
Thanks again for the rating and nomination.