MJ's_MJ Posted May 31, 2014 Share Posted May 31, 2014 My first post in this (or any) forum... - 1986 2.5L 5 speed 4wd X model 265,000 miles - She has been sitting for 4 years and I finally put her back on the road (replaced a leaking gas tank, non-functioning fuel pump, etc.), and then there appeared many electrical problems, some have been fixed and some not yet fixed. After chasing ground problems I have made some progress but there are still more to go. The latest problem is that when I activate the emergency flashers and then press the brake pedal the flashers come to a stop with the internal indicators showing a constant ON/green lamp. This only happens when the brake pedal is depressed, otherwise the flahers and turn signals work fine. Some ancillary problems that I don't believe relate to this issue are a non-functioning radio (it does light up and occasionally make awful noise thru the speaker), and a non-functioning heater blower. I would appreciate any thoughts on this current problem, and hope that you are open to follow on questions because this old girl (not me, the MJ!) has many other issues. Mike Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 31, 2014 Share Posted May 31, 2014 Start by performing the pertinent topics in the link below since it's been setting for years. http://comancheclub.com/topic/36382-cruisers-renix-tips/ Also you would be wise to invest in a set of Factory Service Manuals for your model year so you can troubleshoot intelligently. Link to comment Share on other sites More sharing options...
MJ's_MJ Posted May 31, 2014 Author Share Posted May 31, 2014 Thanks for the reply hornbrod... I have been lurking for a month or so since the MJ came back to life and I have been working on that list of tips for a fews weeks. It was one of the first topics I stumbled upon when I visited this site (thank you for what you compiled). I will continue to follow it thru to completion but this particular anomaly doesn't seem to lend itself to any of the diagnosis/repair steps I have seen so far. I didn't intend to 'skip' any of the steps but was hoping for a shortcut... sometimes I get impatient! Thanks again. P.S. - about the FSM - I use alldataDIY and would like to hear you thoughts on that. Link to comment Share on other sites More sharing options...
shelbyluvv Posted May 31, 2014 Share Posted May 31, 2014 If I remember right the MJ flashers stop flashing when the brake is applied. It is a Safety feature to keep from getting rear ended. The radio is more than likely in need of replacement. The screeching tells me it is burnt up. The blower motor resistor is probably bad causing the blower not to work. Link to comment Share on other sites More sharing options...
MJ's_MJ Posted May 31, 2014 Author Share Posted May 31, 2014 shelbyluvv, I suspect you are right about the radio, it was a low end unit when I installed it and is the most likely culprit there. Would the resistor being bad result in a complete failure (no fan rotation at all) or usually a no LO or no HIGH speed rotation? Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 31, 2014 Share Posted May 31, 2014 Usually when the blower resistor fails it defaults to the HI speed. IF the blower motor itself is good. Pull the motor and do a bench test of the motor with a 12V source (or hot wire it) to see if the motor is functioning. Link to comment Share on other sites More sharing options...
MJ's_MJ Posted June 6, 2014 Author Share Posted June 6, 2014 The blower motor operates at high speed when a hot and ground are applied to it (regardless of the switch position as I would expect). Probing the supply pigtail results in 12+ volts at most positions of the swirch. I thought the resistor was after the connector, but if that were the case would the blower still operate off a hot wire? If the resistor is before the conector why would I still get voltage when probing the supply line? Perhaps the resistor is not failing until a load is applied to it? Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 6, 2014 Share Posted June 6, 2014 Below is the blower circuit schematic. There is a thermal fuse in the middle of the resistor. When this opens due to excess heat, you can see the only 12V path to the motor is when the switch is in the HI position. Link to comment Share on other sites More sharing options...
Eagle Posted June 7, 2014 Share Posted June 7, 2014 If I remember right the MJ flashers stop flashing when the brake is applied. It is a Safety feature to keep from getting rear ended. The radio is more than likely in need of replacement. The screeching tells me it is burnt up. The blower motor resistor is probably bad causing the blower not to work. That's correct. I don't know how it could be considered a safety feature when they didn't do the XJ that way, but the brake lights on the MJ do override the 4-way flashers. Link to comment Share on other sites More sharing options...
MJ's_MJ Posted June 7, 2014 Author Share Posted June 7, 2014 Thanks for the info... I still haven't made any progress by probing but I am suspecting the selector switch/blower switch now. There is continuity of diferring resistance values thru the terminals of the resistor and there is voltage from the power supply pigtail. The rear tail/stop/turn/emergency flasher light issue turned out to be the wrong bulb from a PO, but after investigating I will say in his defense there is an error in the owners manual... it calls for 2057 stop lamps and 1156 turn indicators. In real life they shoule be the same. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 9, 2014 Share Posted June 9, 2014 Thanks for the info... I still haven't made any progress by probing but I am suspecting the selector switch/blower switch now. There is continuity of diferring resistance values thru the terminals of the resistor and there is voltage from the power supply pigtail. The rear tail/stop/turn/emergency flasher light issue turned out to be the wrong bulb from a PO, but after investigating I will say in his defense there is an error in the owners manual... it calls for 2057 stop lamps and 1156 turn indicators. In real life they shoule be the same. Not the same. The 2057 is a dual filament bulb; the 1156 is a single filament. Not interchangeable at all. Image Not Found Image Not Found Link to comment Share on other sites More sharing options...
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