Thread: FAULT: Cattle grids cause hazard ligts to activate? (PUMA)

My first guess would be a loose or wonky inertia switch - the bumps as you go over cattle grids are making the car's computer think you've been in a bit of a prang so it switches on the hazard lights.

Switching the car off and on again resets it. It is not a fault as such but the switch is being over sensitive (if you know what I mean) is.

Either locate the switch yourself (normally in the engine bay on the firewall) to see if it is loose or take it back to the dealer to get them to do it under warranty.

Will be the inertia switch, my D1 used to do it every time it bottomed out or got air on dirt roads... Sounds like yours is faulty if it's that sensitive.

its either loose, tilted or you have a stiff front shock with bad bushes

An inertia switch?!
I thought these cars were meant to be simple ;-)

Does anyone know if this switch feeds into other systems in the car, or is it just for flashing the hazards in an accident? Or what threshold it should be activating?


As for the suspension idea, I'm guessing I'll know pretty quick if I jump on the LHS or RHS of the bullbar whether a shock is rooted?

Originally Posted by Toxic_Avenger

An inertia switch?!
I thought these cars were meant to be simple ;-)

Does anyone know if this switch feeds into other systems in the car, or is it just for flashing the hazards in an accident? Or what threshold it should be activating?


As for the suspension idea, I'm guessing I'll know pretty quick if I jump on the LHS or RHS of the bullbar whether a shock is rooted?

It feeds into the ECU which will shut down (and therefore shut down the fuel etc) if there is a big enough bump. And by that I mean hitting something solid at a reasonable speed.

The indicators flashing on there own is the car's way of saying "Whoa!! What happened then?" but they should certainly not be triggered over a cattle grid.

The kind of bump you need for it to just be the indicators in the kind of one where the moment you hit it you think "Ooof, ****, that was a bit hard." Hitting a badly maintained cattle grid approach at 80kph kind of thing, not 20kph.

Originally Posted by sam_d

The indicators flashing on there own is the car's way of saying "Whoa!! What happened then?" but they should certainly not be triggered over a cattle grid.

The kind of bump you need for it to just be the indicators in the kind of one where the moment you hit it you think "Ooof, ****, that was a bit hard." Hitting a badly maintained cattle grid approach at 80kph kind of thing, not 20kph.

I did a few tests, the cattle grids were those old rickety ones cobbled together with old railway iron. They were rough, but not the kind that you get airborne off of, or loose a wheel down the middle of.

20KM/h approach was fine.
30km/k and upwards tripped it.
...But it didn't kill the engine, so fuelling and other critical ECU controlled aspects were fine. Drove approx 2km with the hazards on, the cows were looking at me funny though

Off to the dealer I guess, I could fix it myself if I had the inclination, but while its in warranty, I'm happy to make it someone else's problem, using their time and coin.

Originally Posted by Toxic_Avenger

I did a few tests, the cattle grids were those old rickety ones cobbled together with old railway iron. They were rough, but not the kind that you get airborne off of, or loose a wheel down the middle of.

20KM/h approach was fine.
30km/k and upwards tripped it.
...But it didn't kill the engine, so fuelling and other critical ECU controlled aspects were fine. Drove approx 2km with the hazards on, the cows were looking at me funny though

Off to the dealer I guess, I could fix it myself if I had the inclination, but while its in warranty, I'm happy to make it someone else's problem, using their time and coin.

Even the most ricketty cattle grids should not be a problem at 30kph. The ECU won't kill the engine until a major (and I mean major) bump but the hazards should be coming on this easily either.

And yeah, make it the dealer's problem while it's under warranty