Any MOT testers here?

TrickyWicky

Joe_Horner wrote: »

Wire a (temporary) permanent feed to the fan?

Not with my luck lol. It's an ECU controlled fan and the only way to start them off is to ground one of the connections via the ECU. Tried grounding it directly to the battery and it does nothing so thats out too!

It's a bl**dy complicated bit of kit and a pain in the grass lol

Joe_Horner

TrickyWicky wrote: »

Not with my luck lol. It's an ECU controlled fan and the only way to start them off is to ground one of the connections via the ECU. Tried grounding it directly to the battery and it does nothing so thats out too!

It's a bl**dy complicated bit of kit and a pain in the grass lol

Even when they're ECU controlled, at the fan end there's just a motor with two connections - a positive and a negative (earth).

Disconnect the wiring to it at the first available plug (probably on the fan itself but may be on a short lead-out) and connect a +ve supply and an earth.straight to the motor. Preferably take the +ve feed from a fuse that's only live when the ignition's on, that way it'll run when the ignition's on and stop when it's off.

If it spins the wrong way (blows air out through the grill instead of sucking it in) then reverse your connections.

TrickyWicky

Joe you misunderstand (and you're not the first to suggest that either). The fans are hard wired to relays. There are no plugs / sockets between the fans and relays to intercept and supply power to. They're relay controlled via the ECU grounding the relays (3 relays - one a fused control relay and the other two for low/high speed fans running in series / parallel). Then the fans are stuck behind a big plastic panel with two radiators behind them. In short what you're suggesting can't be done on this car.

Believe me, i've had other people look at the problem and they've thrown their hands up in the air at it too

AdrianC

TrickyWicky wrote: »

Joe you misunderstand (and you're not the first to suggest that either). The fans are hard wired to relays. There are no plugs / sockets between the fans and relays to intercept and supply power to.

So fiddle with the +ve and earth to the switching side of the relays!

In short what you're suggesting can't be done on this car.

'course it can! It's all a question of how much you want to alter the existing electrics.

Joe_Horner

TrickyWicky wrote: »

Joe you misunderstand (and you're not the first to suggest that either). The fans are hard wired to relays. There are no plugs / sockets between the fans and relays to intercept and supply power to. They're relay controlled via the ECU grounding the relays (3 relays - one a fused control relay and the other two for low/high speed fans running in series / parallel). Then the fans are stuck behind a big plastic panel with two radiators behind them. In short what you're suggesting can't be done on this car.

Believe me, i've had other people look at the problem and they've thrown their hands up in the air at it too

If the relays are accessible then that actually makes it even easier.

Remove all three relays - hopefully they'll either be standard layout or have their terminals marked on them. Assuming they're standard 4- or 5- pin relays, their terminals are like this:




Make up two short jumper cables with a male 6.3mm terminal on each end. Connect one across the "normally open switched" terminals of the control relay socket (pins 30 and 87) and one across the same terminals or either the high or low speed relay depending which you want. The ECU can then do what it likes trying to earth the non-existant coils, you've effectively got two permanently energised relays

TrickyWicky

AdrianC wrote: »

So fiddle with the +ve and earth to the switching side of the relays!

Heh I did that already - I grounded the relays at the main connector in the wing directly to the battery - still no fans :mad:

@Joe Cheers I'll give that a go - assuming i can decipher the existing wiring diagram which is a real nasty beast!

gik

I got my old Brava with a duff radiator fan through two MOT's by running the heater fan on high for the duration of the tests.

colino

You may have another problem if you think your car is over-ecu'd. If there is a cooling fault, that will be in a loop for fuelling too, and may screw your emissions test anyway. What's the fault and why not cure that before hard wiring the relay?
At one point you could get a bare car, with no engine at all, VIC'd, but around here no more.

TrickyWicky

colino wrote: »

You may have another problem if you think your car is over-ecu'd.

Oh yes I'm well aware of that

colino wrote: »

If there is a cooling fault, that will be in a loop for fuelling too, and may screw your emissions test anyway.

Yeah it intermittently grumbles about the fuel injection system being faulty with the ECU light on. Other times you get neither. Stumped if I know but I got another set of injectors at the ready for swapping.

colino wrote: »

What's the fault and why not cure that before hard wiring the relay?

Well thats just it, I really have no idea. I'm suspecting a possible short somewhere in the wiring loom as moons ago if I wiggled one wire the fans would randomly activate. Unfortunately though that trick no longer works and having pulled the wires out of the black plastic tubing, nothing is immediately obvious. It did however have a screwy block connector under the auto tranny which stopped the auto ECU working and consequently stopped the car starting for over a year. Maybe I should take another look at that..

colino wrote: »

At one point you could get a bare car, with no engine at all, VIC'd, but around here no more.

VIC check is different to an MOT and only tests the cars identity / VIN numbers. VOSA won't push cars in and out of their garages and insist all cars are runners - presumably to save on compo claims.

colino

I made mention of the VIC referring to your original post where the engine not running was mentioned, perhaps confused with the MOT and the good old days. Unfortunately as long as exhaust, smoke and emissions have been part of the trial, the complete package must be testable.
What is the car and the fault and have you had it scanned?