2000 Peugeot 306 - Blower fan issues

[VikeeVeekie]

Hi all,

I've been pulling my hair on my 306 lately, and hoping for some pointers what to do here.

When I bought this car in December, the blower motor would fluctuate in fan speed no matter what position the knob was set to. Fixed that by pulling a replacement heater control assembly from the junkyard, all was well until a couple weeks ago. Had the AC turned on (yes that thing holds a charge with no leaks, believe it or not!), fan set to full blast and suddenly it cut off entirely.

Once I got home I started poking around, noticed that the plug of the blower motor was hot and the contacts were corroded. Cleaned em up with some contact cleaner, used a screwdriver to make sure that the plug has a tight fit on the pins which did some wonders.

However, now when the knob is set to full blast, the motor still has a life of it's own. I measured the voltage to the blower: 13v on low, 8v on full with the blower disconnected. Once I plug it in, some electrical connection can't seem to handle the amp draw and the incoming voltage at the blower will start to fluctuate when it tries to pull full power. I checked my fusebox and sure enough the fan relay was burned up, but issue remains with even with a new relay.

I've only just replaced that relay today, and noticed that after a while, the fan will run at proper full speed and will continue to do when I play with the control knob. Somewhere along the circuit, seems it warms up to the point it makes sufficient contact after a while.

Sorry for the wall of text here! I've been trying to chase this electrical gremlin for a while now and it's starting to drive me crazy hearing that fan go haywire while I'm on the road. Any ideas what I could look into and that I have possibly overlooked? Thanks so much for your replies!

[Peter.N.]

You have been doing the right things. I am not familiar with the electrics on this car, don't know if it has a transistor regulator or a resistor pack but had quite a few problems on the XM's I used to run due to the fuse holder in the engine compartment burning up and the motor plug contacts, seems the whole system provided sufficient current without burning something out.

Have you checked the motor voltage again since you did the remedial work? Is the regulator in the motor or separate? If the motor voltage is constant but the speed varying the fault must be in the motor or control if its in the motor.

Peter

[VikeeVeekie]

Hi Peter,

Today I've taken another crack at diagnosing the issue, and found out that my rheostat was faulty. In 306's with a variable speed controller, the rheostat is bolted to the motor housing but you can take it out if needed.

Poking around with my multimeter some more, I found out the rheostat always received a steady 12v when testing pins 1 and 3. Testing pins 1 and 2, I was able to find the control signal which was a steady 5v during a call for full speed, 0.47v on low. Then I took the blower apart and measured the motor's incoming power and that's where I found my voltage drop. Instead of a proper 12v, I was only getting about 7-8 which then ever so slightly started increasing to the ballpark of 11v as the rheostat started heating up.

I've pulled a used blower assembly from the junkyard, tested that one and it's been acting completely fine now! It's been a challenge figuring this out since the electrical diagrams in the Haynes manual actually don't match with my vehicle. All those diagrams show a 4 speed switch and 4 wires or so going to a resistor pack, which this vehicle doesn't have at all. It's just three wires going straight to the blower assembly (or well, straight to the rheostat) from the center console.

[Peter.N.]

There you are then, you don't have to have been a TV engineer for 50 years to sort it out, very satisfying when you find it, well done.

Peter