5 replies to this topic

[Jamie_RoverMini35]

a while back i bough an electronic oil pressure gauge and fitted it today i was wondering if the way i have done it is correct... so i got 2 core wire wired it all up fine but what i done was put one wire in the end of the old connector of the oil pressure switch and pushed it onto where it has been and the other piece of wire to earth and connected it all up to the gauge, however the oil pressure light stays on but the gauge works fine i assume this is all ok? and the lights only on cause ive bridged it out?
cheers
Jamie

Edited by Jamie_RoverMini35, 23 December 2012 - 07:47 PM.

[dklawson]

I may have misinterpreted what you typed so please correct my misunderstandings.

Your new gauge should have come with its own electric sending unit. You MUST use it with the gauge. The original oil pressure light switch is a switch, not a sending unit.

If you want to use both the switch and the new gauge you need a "T" fitting to go into the block where the original oil pressure switch was installed. The original switch goes into one leg of the "T" and the sending unit for the new gauge goes into the other leg of the "T". The original oil pressure light wire goes back on the original switch. A second (new) wire will go from the new sending unit to the input wire on the new gauge. Then your gauge (being electric) will require an earth and switched power connection.

I don't understand how you have used the 2-conductor cable but if you have not wired the original switch to its original wire, you may indeed have somehow connected the warning light permanently to earth which will leave the light on all the time.

[Jamie_RoverMini35]

ah i think you interpreted correctly, so i need a sender unit and not the standard switch that is in the block just now? just im wondering because im getting a reading on my gauge ?

[tiger99]

You are not getting a meaninful reading on your gauge, only whether the pressure switch is off or on, which will make the needle move, presumably to zero or maximum. It is not telling you pressure at all. As Doug says, you must fit the proper sender unit, and it is advisable to use a T piece to keep the warning light switch too.

The gauge should have been supplied with the correct sender. The electrical requirements vary between manufacturers.

[Jamie_RoverMini35]

my light wasnt working at all when i bought the car so i thought i would fit the gauge, so presumably if i had no oil pressure i wouldnt get a reading from the gauge but i am so isnt it working in a way? just not 100%.

[dklawson]

No, it's really not working if you have hooked the gauge up to the pressure switch instead of installing the sending unit. It's like that expression, "even a broken clock is right twice a day".

What you know from what you have installed/changed is that the oil pressure warning lamp bulb works. That suggests you need a new switch for that indicator circuit. If you want the gauge to work properly there isn't a solution other than fitting its dedicated sending unit.