Mystery Voltage Draw - ZR-1 Net Registry Forums

Locobob · 09-03-2015

I noticed my battery getting drained when sitting for a few days, just discovered my passenger side visor mirror light was on... DOH!

Bob Eyres · 09-11-2015

A little update here. I'm away from the car and just had a phone conversation with the guys that are working on it.
Last week they told me that they'd found a shorted out driver's side seat switch at the back of the console, (I never knew the seat motor didn't work because I never really move it.). We ordered a switch from a salvaged C4 and installed it along with the harness and plug it came with. Now the seat works, but it kept blowing fuses.
Today they tell me that in the power supply harness to the seats, after they unwrapped the tape on it they spotted a fried 3amp diode on the back of the incoming power wire in the harness, they separated the leads, but have not replaced the diode yet. The seat now works, but we're wondering wether to replace that diode, or what to do next.

Just a reminder. This is a relatively unmolested ZR-1 that I've had for over twenty years with no real electrical problems or modifications to the electrics.

I'm totally clueless as to electrical aspects of the car, so on Monday, Dick, the mechanic that's working on it is going to sign up to this forum to talk direct to anyone that might steer him in the right direction.

BTW, could my car have caught the dreaded British electrical disease from some of it's Lotus designed components?

Marc Haibeck · 09-12-2015

Hi Bob,

The diode is there to attenuate voltage spikes that the motor sends out when it is turned off. The voltage spikes can cause erroneous operation of electronics in the car. The diode should be replaced. It's a common 1N4002 diode. It needs to be installed with the correct polarity. The diode should be available from a computer or appliance repair parts store.

Bob Eyres · 09-12-2015

Thanks Marc

We'll get a fresh one in there, and I'll post what happens.

09-03-2015	#1
Locobob Join Date: Jan 2004 Location: Portland, OR Posts: 1,047	Re: Mystery Voltage Draw I noticed my battery getting drained when sitting for a few days, just discovered my passenger side visor mirror light was on... DOH! __________________ Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368

09-11-2015	#2
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 813	Re: Mystery Voltage Draw A little update here. I'm away from the car and just had a phone conversation with the guys that are working on it. Last week they told me that they'd found a shorted out driver's side seat switch at the back of the console, (I never knew the seat motor didn't work because I never really move it.). We ordered a switch from a salvaged C4 and installed it along with the harness and plug it came with. Now the seat works, but it kept blowing fuses. Today they tell me that in the power supply harness to the seats, after they unwrapped the tape on it they spotted a fried 3amp diode on the back of the incoming power wire in the harness, they separated the leads, but have not replaced the diode yet. The seat now works, but we're wondering wether to replace that diode, or what to do next. Just a reminder. This is a relatively unmolested ZR-1 that I've had for over twenty years with no real electrical problems or modifications to the electrics. I'm totally clueless as to electrical aspects of the car, so on Monday, Dick, the mechanic that's working on it is going to sign up to this forum to talk direct to anyone that might steer him in the right direction. BTW, could my car have caught the dreaded British electrical disease from some of it's Lotus designed components?

09-12-2015	#3
Marc Haibeck Join Date: May 2007 Location: Addison IL Posts: 252	Re: Mystery Voltage Draw Hi Bob, The diode is there to attenuate voltage spikes that the motor sends out when it is turned off. The voltage spikes can cause erroneous operation of electronics in the car. The diode should be replaced. It's a common 1N4002 diode. It needs to be installed with the correct polarity. The diode should be available from a computer or appliance repair parts store.

09-12-2015	#4
Bob Eyres Join Date: Jul 2005 Location: Jupiter, Fl. Posts: 813	Re: Mystery Voltage Draw Thanks Marc We'll get a fresh one in there, and I'll post what happens.