Front Heater fan stopped working

[hijimhere]

Using the work sheets and fuse config I have been investigating - strangely when the dash switch is on the rear blower works - if the switch is in the off position the rear will not operate. (I don't think this has anything to do with the fault - just an observation. I have had the resistor pack off - I have continuity on all four terminals from the center single which seems to be the supply terminal - I have different impedance figures for the four. The next step is to check that a supply is there - I couldn't be certain that the meter probe was in contact so I decided to pull the connector and go in from the front of the connector and simply earth the other probe. With the meter set to 20v I could only get 0.24 when earthing. it looks as if there is no supply to the connector. I check the fuses, one on the board was ok, one pink on the block under the bonnet was ok. There is mention of a thermo fuse on the work sheets but no clue as to where this is on the vehicle.. the fan rotates freely and very little in the way of end float. I am flumoxed - any suggestion where to go next? Behind the block terminal there is another connector that goes into what could be a thermo fuse. Any help would be appreciated thanks.

[Simon Jones]

Have you tried applying 12v direct to the fan motor? Have you got manual or digital controls? If the latter, it's a transistor pack rather than resistor so not readily testable with a multimeter on resistance setting.

[hijimhere]

Manual that has 5 spade resistor pack - not tried 12v direct - no voltage at the pack ign on switch on

[hijimhere]

Replaced resistor pack - ineffective - reading a lot about a transistor on the fact sheets - there is the suggestion that this is part of the resistor pack - can any one verify that it is or is it located elsewhere?

[hijimhere]

12V direct to motor = motor working fine - no squeaking & runs very freely.

Relay working

Switch working

checked all fuses - two engine bay 30 and 60 amp plus 15amp on board ok.

Fan working on ignition live - so ignition switch ok

substitute resistor pack - negative fan still not working

all that seems to be left is the transistor!!!

[Simon Jones]

Manual controls use resistor pack while digital controls use a transistor so you won't have one.

[hijimhere]

Much appreciated, does it have a thermo cut out?

[Simon Jones]

Not sure about the thermo cut out but that would only kick in when the load/temperature got too great. Might be worth removing the control panel and having a poke around the back. I believe the end covers pop off and then it is removed using a U-shaped removal tool (similar to that used for getting the stereo out).

Schematic here: http://lushprojects.com/bongopartsmk2/c ... 1of02.html

[hijimhere]

Many thanks

[hijimhere]

so I went up to Market Rasen for a weekend total road trip 250 miles with a bit of gadding about - got home last night after very nice weekend (my birthday on Saturday). Still no front heater fan. Went dentists earlier and called into village shop on way back, as I stopped outside the shop the front fan came. It seemed to work ok - so I thought lets switch ignition off and on - I did the fan ran but at much reduced speed - did on/off with ignition fan came on at normal speed 4 - to cold and wet to look further. One thing I did notice I had two carriers bags with stuff in the passenger footwell. One of the bags had gathered some water. I know the screen channel drainage pipe is clear as I had checked that. I may have a leak on that side. It was raining quite heavy on my round dentist trip - the plot thickens...........

[g8dhe]

Have you actually had the Fan motor out and cleaned it? If the thermal fuses in the resistor pack have popped, at any time, then it indicates that the motor itself is having a problem, normally muck and corrosion products after having been doused in water causes the problem, repairing the thermal fuses gets it going again but the problem will only come back a short while later.

[hijimhere]

Still looking for any thermal fuse - from what you are saying its integral to the resistor pack - I substituted/replaced the pack which made no difference - provided a direct feed to the motor via the connector, worked fine, manually rotated the fan very free no signs of stiffness, end float minimal. That was all in situ so i think it must be time to strip out the motor - when the sun next appears!

[g8dhe]

There down the sides, brass fingers soldered together the heat causes the solder to melt as below down the side;


Check the connector on the rear of the control unit, it has been reported once that it had come loose and causing odd problems I think after the unit had been removed for some reason.

[hijimhere]

Going in with meter tomorrow - very much appreciate the help I have looked for continuity/open circuit on both resistor packs I have - got continuity ok but perhaps its time to strip the orginal down and look internally - could get continuity if a thread of solder still there. I won't go into the discovery of yesterday that the HRW warning light stays on even with the key out - there must be a darkened room I can use locally lol.

[hijimhere]

update - Fan Circuit now and HRW both live if left on with the ignition off and key out? Some shenigans going on for sure!