The 75 and ZT Owners Club Forums - View Single Post - Fitting alternative sport mode switch on indicator stalk

goltho · 10th April 2018, 12:43

So it seems to me that this relay would in fact work, provided I ran a 12V- supply to pin 30 instead of the 12V+ shown below. (The diagram uses 56 & S in lieu of the more common 85 & 86 respectively.)

It would then alternately close and lock a ground circuit to 56a (Econ mode) and 56b (Sport mode) whenever the momentary switch was pressed on the indicator stalk. The only difference I can foresee from the manufacturer's arrangement would be the continual grounding by the relay rather than the momentary grounding by the OEM switch. It's the transmission ECU which deals with the signal; would it dislike a continuous signal?

10th April 2018, 12:43	#10
goltho Can't help myself Rover 75 CDTi 2005 Join Date: Jan 2018 Location: Lincoln Posts: 871 Thanks: 469 Thanked 150 Times in 113 Posts	So it seems to me that this relay would in fact work, provided I ran a 12V- supply to pin 30 instead of the 12V+ shown below. (The diagram uses 56 & S in lieu of the more common 85 & 86 respectively.) It would then alternately close and lock a ground circuit to 56a (Econ mode) and 56b (Sport mode) whenever the momentary switch was pressed on the indicator stalk. The only difference I can foresee from the manufacturer's arrangement would be the continual grounding by the relay rather than the momentary grounding by the OEM switch. It's the transmission ECU which deals with the signal; would it dislike a continuous signal? __________________ R75 C2 RJBLH Connoisseur CDTi Auto Saloon • Built 08/02/2005 @14:57 hrs: Registered 26/08/2005 • 122nd of 141 built that day • British Racing Green Pearlescent (HFF) • Sandstone leather with black piping (SPJ) • 137,000 miles Last edited by goltho; 13th April 2018 at 14:52..