Hello all,

So in the aftermath of the coolant failure/the nipple of the expansion tank breaking off and spraying coolant throughout the engine bay, I’ve now got a new issue immediately thereafter in my XJR.

BONNET OPEN warning ⚠️ started after a few days along with the dreaded random activation of the car alarm. Thankfully not happening at home since the car is unlocked in the garage. But very embarrassing when it goes off when I’m out and about town. I’ve tried opening/closing the bonnet. No change. Both mechanisms look fairly dirty. Would not be surprised if coolant got into the mechanism/s and fouled them. Thinking a bit of GOO GONE sprayed inside and some cleaning with a shammy as best as I can?

Tried rinsing then with hose but water alone did nothing.

Otherwise it’s back to mechanic…?

 

Very common problem, and the almost universal solution is to just give it up and pull the connector from the switch on the hood latch, and jumper the wires together. Your car won't be able to detect somebody breaking the hood open, but it won't keep randomly alarming or telling you the bonnet is open.

This thread has pics of what you're looking for.

You an replace the switch, as it's probably damaged, but how important is detecting the bonnet open condition, actually?

 

Thanks for this.

Yeah, I was reading about others’ and their troubles. I assumed that given the timing, the coolant must’ve gotten into the mechanism and gunked it up. That sticky solution, particularly in the summer heat, could not have been good.


I had the BONNET OPEN ⚠️ warning on again today soon after I left the house. I’ll try the GOO GONE and when that fails then I guess it’s time to have the mechanic clip the wire as you directed. I don’t think anyone would be attempting to break into the engine bay (fingers 🤞&#127995.

 

Before you use the Goo Gone (which might be somewhat conductive and leaves residue); Stop by your local Auto Parts place and ask for a can of Contact Cleaner. Something similar to this:
https://www.autozone.com/miscellaneo...tact%20cleaner
Then remove hood switch, spray clean switch and the contacts on the connector (male and female).

 

Thanks for this suggestion. Hadn’t thought about that (residue from GOO GONE itself). Just wondering if this contact cleaner will manage to get through any gunked on coolant? Guess I don’t know until I try. I am not a tinkerer though so if the issue involved having to partially disassemble, I would rather give it to the mechanic especially since both hood clasps seem to be involved anyway and could use a good cleaning. Otherwise I could spray the hell out of it from up top and hope for the best

 

The switch is behind one of the latches (the driver's side) and you'd never in a million years reach it with any cleaning spray from the exterior with the hood closed. You can't even reach it with a spray when it's in place and the hood open. To try to clean it, you have to remove it from the latch and put it back afterward, and as far as I'm concerned, if you're going to the trouble of removing it, just disconnect the connector and jumper the wires together to permanantly "close" the switch's circuit and throw the switch away.